The image of the luminosity of the divine nature of Christ in the Western European temple decoration of the IV-VIII centuries.

Khripkova Elena Avenirovna ORCID: 0000-0002-8101-680X PhD in Art History Associate Professor; Department of Theory and History of Art; Russian State University for the Humanities 15 Chayanova str., room 5, office 303, Moscow, 111399, Russia samary@inbox.ru Other publications by this author

In sacred art and in religious spiritual texts, images of fire and light occupy an important place, which for centuries have been and are receiving special attention from philosophers ^{[1, 2]}, theologians ^[3-5], patrons and customers, researchers ^[6-16] and artists who directly performed and perform the task of visualizing the divine image or divine presence in the creation of temple decorations, liturgical books, liturgical utensils and the temple building itself. It is hardly possible to list all the authors, ancient and new, who have ever written about light and color in the ancient and medieval philosophical and theological traditions, or translated and researched these texts. "From Neoplatonism, from St. Augustine, light in Christian thought is an essential and necessary element of beauty: she is, ... absolute beauty, like: "lux et ordo".  She is the most obvious demonstration of God in the material world..." ^{[16, p.14-15]}. 

The subject of this study is the artistic tradition of representing the luminosity of Christ in Western European temple decorations of the IV–VIII centuries, in which the image of the Savior's halo plays a special role. The objects of this study are fragments of the monumental decoration of the IV–VIII centuries. the main Western European Christian churches that have preserved the images necessary for analysis. Due to historical circumstances, these are the monuments of Rome, Ravenna, Milan, Naples, Capua, Castelseprio and Cividale del Friuli.  The purpose of this work, which forms the first part of the study, the chronological framework of which covers the period from the IV to the XIII centuries, was to form an idea of the formation and development of the artistic tradition of representing the theme "I am the light of the world" in the period of the IV–VIII centuries, which is an important stage in the process of studying the specifics of the visual language of Western European medieval art. To do this, on the basis of formal stylistic, iconographic and typological methods of analysis, it is necessary to describe and analyze the preserved images, identify and systematize artistic techniques, the main typological features and iconographic characteristics of representations of the luminosity of the divine nature of Christ. At the same time, based on the work of a number of previous researchers, in particular F. Boespfluga ^[6], A. Didron ^[7] and V. E. Suslenkov ^[12], we will pay special attention to the issue of systematization of typological characteristics associated with the representation of the halo of Christ in preserved Western European mosaics and frescoes of the IV–VIII centuries.

The image of the luminosity of Christ in the Western European art of the IV century.

In the text of the Holy Scriptures, we repeatedly find words defining the luminosity of the divine nature of Christ: "I am the light of the world" (John 9:5), "I, the light, came into the world so that whoever believes in me would not remain in darkness" (John 12:46), I am the light of the world; whoever follows me will not walk in darkness, but will have light life" (John 8:12), "God is light, and there is no darkness in him" (1 Jn.1.5) ^[17].

Images of the radiance above the head of Christ come to the Christian tradition from the ancient world along with the images of Helios, Apollo and Sol Invictus, whose veneration as representatives of the Sun God reaches its apogee in the III–IV centuries.  The variety of solar cults of ancient Rome, their connection with the cult and iconography of the imperial image, as well as the connection of the cult of Emperor Constantine himself with the worship of the Sun are covered in detail in the work of V. E. Suslenkov ^[12].

Fig.1. The image of Helios in a chariot on the metope of the temple of Athena in Troy, beginning. IV century BC, Pergamon, Berlin. Photo of the author.

Fig.2. Christ-Helios. Mosaic of the vault of the "mausoleum M" (tomb of the Julii) under St. Peter's Basilica in Rome. Image source: ^{[18, p. 80, fig.74]}.

The image of Helios in a chariot (IV century BC) on the metope of the temple of Athena in Troy, presented in the Pergamon Museum in Berlin (Fig.1), is an excellent iconographic model for Christ in the image of a solar deity (Apollo, Helios, Sol Invictus)  in the chariot. Christ-Helios can be seen on the mosaic of the vault of the "mausoleum M" (tomb of the Julii) under the Basilica of St. Peter in Rome (fig.2), which dates back to the III–IV centuries ^{[12; 18, p. 80]}. His Apollo-like face, surrounded by a halo with diverging rays of light, reproduces a very stable image of the sun god, similar to that presented on the floor Roman mosaic of the II century. in the archaeological museum of El Djem in Tunis (Fig.3), or in the mosaic of floors of the turn of the III–IV centuries.  in the Archaeological Museum of Sparta (fig. 4). 

Fig.3. Image of Apollo-Helios, II century., El Djem, Archaeological Museum, Tunisia. Image source: https://simbolosmitologicos.wordpress.com/2011/09/06/simbolos-apolo .

Fig. 4. Personification of the Sun. Roman floor mosaic. III–IV centuries. The Archaeological Museum in Sparta. Photo of the author.

Another iconographic version of the representation of the sun-like Christ is a variant of the face in a diadem with diverging rays, similar to the colossus of Rhodes, created by the sculptor Hares from Lindos in the III century BC, which also began to be used to represent Sol Invictus. This image is represented on the 313 gold solid from the cabinet of medals of the Paris National Library (BNF) (Fig. 5). 

Fig.5. The image of Emperor Constantine and Divus Comes. Image source: ^{[18, p.15, fig.11]}.

Two profile faces on the medal show images of Emperor Constantine and a character in a radiant diadem behind his back. R. Krautheimer calls the latter the divine co-ruler of Constantine ^{[19, p.36]}, A. Grabar sees in him Alexander the Great, representing the imperial ideal ^{[18, p.15]}, V. E. Suslenkov sees in this character the image of Helios-Sol ^[12].

The fusion of solar images of the highest deities of the pagan pantheons with the image of Christ ^[12]; ^{[20, pp. 125-145]} was a natural consequence not only of the definition of God in the text of St. Peter. John (1In.1.5), but also the direct influence of the cult of the earthly emperor on the image of the heavenly emperor. The fact that in 330 Constantine placed his statue in the image of the Sun on a high column in Constantinople, testifies to his direct comparison with the solar deity, "his images completely copied the iconography of Sol Invictus: a solar crown or halo around the head in his images on coins, undoubtedly testifies to the peculiarities of how Constantine's worldview as well as about his religious policy, in which the imperial cult merged with the cult of the Sun" ^[12].

After Constantine the Great recognized the Christian god as his divine patron and began large-scale construction of Christian churches under the patronage of the imperial family, Constantine's entourage, addressing the emperor, did not always understand what to call the new God. R. Krautheimer cites several appeals of this kind: ""The Supreme Creator, who has as many names as there are languages... imparting power to all creatures... the ruler of all Heavens", "The Divine Mind that appears and opens to you alone, entrusting the daily care of us to the younger gods!", "The Divine Mind that ensures the existence of the world permeating all elements" ^{[19, p. 37]}.  At the same time, in the Christian environment, Christ was called "The Light of Truth", "The Sun of Truth", "Apollo the true", emphasizing the direct connection with solar cults. In the texts of Christian authors of the IV–VI centuries, there are constant references to the luminosity of Christ. St. Ambrose of Milan writes in De Spiritu sancto: "The Father is light, the Son is light, and the Holy Spirit is also light" ^[21].   Sv. Augustine addresses Christ: "Oh, my Light! without You, I am in darkness: shine on me!" ^{[3, p.14]}, calls him "The Intelligent Light", "The Light of the world" ^{[3, p.20]}, "the chief of light", "the light from the light" coming from the "Father of Lights" ^{[3, p.34]}.  Peacock of Nolan in his poems calls Christ "the Light of truth", "The Sun of truth", pouring out "his rays on our hearts" ^[22] and addresses him with the words "Greetings, O true Apollo" ^[23].  The representations of the luminosity of Christ discussed above, based on his association with solar cults, are often associated with an element of uncertainty in the interpretation of these images. Their belonging to Christian programs is often determined by the presence of other biblical themes and images in the scenery of the space under consideration. For example, in the tomb of the Julii under St. Peter's Basilica in Rome, in addition to Christ-Helios, there is also an image of the plot "Jonah and the Whale" ^{[18, p. 80]}.  In the earliest depictions of Christ with a simple halo, this ambiguity disappears. Examples of this kind can be seen in various frescoes in the catacombs of the Commodila in Rome. The fresco of the vault of the cubicle of the Lion shows a chest image of the Lord in a square frame on a blue background with stars, with a simple transparent halo clearly outlined by a red and brown line, and the letters "alpha" and "omega" on both sides of it (Fig. 6). This painting dates from 375-380 ^[24].  The circumference of the transparent halo is double, reinforced inside with several dark-colored lines.

Fig. 6. Christ. Fresco of the vault of the cubicle of the Lion in the catacombs of Commodila, Rome. IV century.

Image source: https://art.biblioclub.ru/picture_47136_katakombyi_komm/

Fig.7. The scene "Giving the keys", catacombs of Commodila, Rome. IV century. Image source: ^{[25, p.31, fig.59]}

In another composition from the catacombs of Commodila, decorating the tomb of the martyr, there is a scene of the "Giving of Keys" with images of the martyrs included in the composition.  In the center of this scene, between the apostles Peter and Paul, Christ sits on a transparent sphere, holding an ornate codex in his left hand and handing the keys to the Apostle Peter ^{[25, p.31]}. In this case, the halo of Christ, as well as that of the apostles, is colored yellow and surrounded by a thick brown contour with a thin white line inside it (Fig. 7).  

A more complex two-tiered composition depicting Christ in the upper tier and the martyrs worshipping the Lamb in the second, is found in the catacombs of Peter and Marcellinus in Rome in the cubicle of Saints (IV century).  Christ sits on the throne, the apostles Peter and Paul surround him from two sides. The transparent halo of Christ in this representation is outlined by two lines: red and greenish-blue, the color of which has been significantly lost (Fig. 8). Inside the halo above the head of Christ, one can distinguish the sign of the chrysma. The letters "alpha" and "omega" flank the face of the Savior, referring to the words  Revelations of John (22:13): "I am Alpha and Omega, the beginning and the end, the First and the Last." In all the cases described, Christ is represented far from being young, with a beard and long hair.   

Fig. 8. A fragment of a fresco depicting Christ in the cubicle of Saints in the catacombs of Peter and Marcellinus in Rome, IV century. Image source:^{[26, S.253, taf.252]}

Among the Roman monuments of the IV century, two more images of the Lord with simple halos should be noted. They are found in the scenes that adorn the two side apses of the Mausoleum of St. Nicholas. Constants and are made in the mosaic technique. V. N. Lazarev refers them to the end of the IV century and interprets them as Traditio legis and Traditio clavium ^{[27, p.26]}. In one of them, the Lord appears in the form of the Creator and Ruler of the world, with a beard and long hair, sitting on a heavenly sphere. Its halo reproduces a bright white glow, smoothly turning into a sky-blue one. The intensity of the color increases gradually, closer to the border of the halo, when the color turns dark blue, however, the halo border is missing (Fig.9). Letters and signs are also missing in this image. In interpreting the plot, given the Old Testament nature of the scene, one can rather agree with V. E. Suslenkov, who sees Moses receiving the tablets here ^[12].

Fig. 9. The Face of Christ. A fragment of the mosaic of the side apse of the mausoleum of St. Constance is in Rome. Photo of the author.

Fig.10. Fragment of the "Traditio legis" scene. Mosaic of the side apse of the Mausoleum of St. Constance is in Rome. Photo of the author.

In another niche, Christ is represented with long blond hair, young, beardless, but with the same sky-blue halo, the intensity of the color of which increases to the border of the halo, gaining blue. Above the head of Christ, on a white background outside the halo, a small sign of the cross is clearly visible (Fig.10). Images of Christ with a cross-shaped halo will appear in monumental painting much later. One of the earliest images of this type in the catacombs of Generosa Y. Villepert dates the first half of the VI century ^{[26, S.261, taf.262]}. It is located in the center of a symmetrical composition, where the Savior with an opaque cross-shaped halo is surrounded on both sides by two saints with simple halos (Fig. 11). The halos of Christ and the saints are the same as those of Christ in the scene of the "Giving of Keys" in the catacombs of Commodila. They are yellow in color, outlined by a thick brown line with a thin white outline inside.

11. Christ and the Martyrs. A scene from the catacombs of Generosa. VI century. Image source: ^{[26, S.253, taf.252]}

So, it can be stated that in the first Christian images in Roman monuments of the IV century. to visualize the idea of the luminosity of Christ, that is, his divine ability to emit light, two types of images are used, the classification of which, based on the nature of the Savior's halo, is given in the Table 1. The first variant (type A) is a direct repetition of the iconography of the luminous gods of antiquity. In this case, it is either a radiant diadem like the Colossus of Rhodes, or a halo with rays like Helios or Apollo. The second option (type B) is an image of Christ with a simple round halo, as in the catacombs of Commodila (Fig.7), or in the catacombs of Peter and Marcellinus in Rome (Fig.8). The halo may be transparent or filled with yellow, symbolizing radiance and light, may have a clear dark border with a thin a white line inside, or it may represent a smooth transition from white or sky-blue to blue and not have a specially outlined border, as in the mosaics of the mausoleum of St. Constance in Rome.   Among the possible iconographic characteristics and attributes in the representation of the image of the Christian god, originating from solar cults, V. E. Suslenkov refers to the gesture of the raised hand of the Savior, merged with the "traditional Roman gesture and pose of an orator and a triumphant", transformed into a gesture of blessing, as well as a sky-blue sphere-the throne and the sphere in the hand of Christ, which can be to see in the mosaics of the mausoleum of St. Constantia in Rome and other monuments ^[12].   Without denying the possible connection of these images with the solar cult, it should be noted, however, that the representation of the Lord sitting on the sky-blue sphere in the biblical context has a direct connection with the text of the prophet Isaiah (Isaiah 66:1), repeated in the speech of the first Martyr St. Stephen in the Acts of the Apostles (Acts 7:49): "Heaven is my throne, and the earth is my footstool."

Table 1. Variants of the representation of the radiance above the head of Christ in Western European monuments of the fourth century.

Representation of the luminosity of Christ in Western European temple decorations of the 5th–8th centuries.

 The vast majority of the surviving early Christian temple decorations were made in mosaic material, where the material itself, imitating the radiance of precious stones, indicates the celestial localization of the scene. On the perception of colored glass by medieval society as precious stones and the endowment of this material with their properties, J. R. R. Tolkien writes. Gage ^[8], L. Grodeski [16. p.12] and a number of other researchers ^{[14; 15]}.  Precious stones, natural and artificial, that is, stained glass and mosaic material, along with other properties, were attributed the ability to emit light — a quality inherent in God, which was perceived as one of the manifestations of the divine presence.

One of the most striking images of Christ in the Roman monumental decoration of the beginning of the 5th century is the mosaic of the apse of the Church of St. Nicholas. Pudenzians with a very complex and filled with various meanings program, in the center of which is the image of the Lord with a golden halo in a white shining edging. He is depicted as the heavenly emperor, who in golden robes sits on a red cushion of a golden, jeweled throne (Fig. 12). Above the figure of Christ, on Golgotha, there is a golden cross decorated with precious stones, which vertically extends over the entire upper part of the composition.  This cross shines like the sun against a background of white, blue and golden clouds, representing, on the one hand, a sign of victory, recalling at the same time the victory of Emperor Constantine over Maxentius in his battle for Rome, and the victory of Christ over death. On the other hand, the golden cross in heaven, surrounded by symbolic Tetramorph beings, visualizes the divine presence, forming, together with the anthropomorphic representation of the Lord, a representation of the Christological dogma about the unity of the divine and human natures of the Savior.

Fig. 12. Mosaic of the apse of the Basilica of St.Pudenzians in Rome, V century. Photo by the author.

Golden flashes in the sky and on the roofs of buildings show the light reflected from the radiance of the Lord. This light is slightly darker than the brightest shining point, which is the center of the entire composition. This point is nothing but the light golden halo of Christ. The letter "L" can be read on Christ's clothes, which, apparently, is an abbreviation of the Latin "Lux" (Light), recalling the text "Ego sum lux mundi" ("I am the light of the world"), although the letter "L" can also be considered as an abbreviation of the Latin "Lex" (The Law). One interpretation, in this case, does not exclude the other at all. The color scheme of the composition supports the explicit symbolism of imperial (red, gold) and celestial characteristics (cyan, blue, white, gold, red). The golden, red and white colors are also associated with the image of the sun's disk in the sky, the same image is referred to by the bright golden halo of Christ with a white border (Fig.13).

Figure 13. Christ. A fragment of the mosaic of the apse of the Basilica of St.Pudenzians in Rome, V century. Photo by the author.

Fig. 14. "Giving the law". A fragment of the mosaic of the arch of the Baptistery at the Duomo of Naples, V century. Image source: https://ru.pinterest.com/pin/778770960550961920/

The image of Christ with a beard and long hair in the scene "Giving the Law" is represented by the mosaic of the Baptistery at the Duomo of Naples. This example is close in time to the mosaic of the Church of St. Peter the Great. Pudenzians in Rome. Christ stands on a blue and white sphere in golden robes, the draperies of which include tesserae of yellow-beige, white, blue and gold in various shades.  Its golden halo, surrounded by a light beige edging, also contains blue tesserae, creating a flickering effect (Fig. 14). The solar color symbolism is clearly read here. The translucent sky-blue sphere and the heterogeneity of the halo structure bring this image closer to the mosaics from the mausoleum of St. Nicholas. Constantia in Rome (IV century) and with mosaics of the beginning of the 5th century in the Chapel of San Aquilino in the Church of San Lorenzo Maggiore in Milan. The composition representing Christ and the apostles in the Chapel of San Aquilino also uses the effect of flickering in the representation of a golden background. The young beardless Christ of the Apollonian type is represented here in white robes, shining with iridescent draperies interspersed with golden tesserae (Fig.15). 

Fig. 15. Christ with the apostles. A fragment of a mosaic in the Chapel of San Aquilino in the church of San Lorenzo Maggiore in Milan, V century. Photo by the author.

Bright orange flashes can be seen on his face and the faces of the apostles, and his golden halo includes the letters "alpha", "omega" lined with white tesserae, and a chrysanthemum of white divergent rays enclosed in a bright white border. 

Golden robes, a golden halo, uniform and without edging on a sky-blue background, light orange highlights on the face decorate the image of Christ the Good Shepherd in the famous mosaic of the mausoleum of Galla Placidia in Ravenna (V century), whose face is E. Redin rightly refers to the Apollo type (Fig. 16), which also refers us to solar semantics ^{[28, p. 71]}.

16. Christ is the Good Shepherd. A fragment of the composition in the Mausoleum of Galla Placidia. Ravenna, V century. Photo by the author.

In the mosaics of the triumphal arch of the Church of Santa Maria Maggiore in Rome (V century), the golden background is used almost constantly in the middle register of each scene, and in the mosaic panels of the central nave it is used fragmentally to highlight certain fragments (Fig. 17, 18).

Fig.17. The scene of the "Adoration of the Magi" in the triumphal arch of the Basilica of Santa Maria Maggiore in Rome, V century. Photo by the author.

Fig. 18. Abraham's Hospitality". Mosaic panel of the central nave of the Basilica of Santa Maria Maggiore in Rome. Photo of the author.

Two scenes are of particular interest to us: the "Adoration of the Magi" in the Arc de Triomphe (Fig.17), and the mosaic panel of the central nave "The Hospitality of Abraham" (Fig.18). In the first case, the young Christ sits on the imperial throne, decorated with precious stones, and also has a golden halo with white edging, inside which reads the sign of the cross. The halos of Christ and the angels differ, but all show different versions of the representation of the luminous nature. Angelic halos are of two types — blue and white with a brighter white border. Christ and the angels are represented in shining white robes.

The second example is much more complicated.  The composition of the mosaic panel consists of three scenes: Abraham meets three husbands, Abraham talks with Sarah, Abraham serves the Trinity at the table. In the first scene, the Trinity is revealed as three men in shining white robes with blue-white halos, and only one of the persons of the Trinity is enclosed in a blue-white mandorla, denoting the radiance of the Glory of the Lord. In the lower tier, in the scene of the actual "Abraham's Hospitality", all three persons are presented in the same way, in white robes with shining white halos on a smooth golden background separating the divine space from the space where Abraham is located.

  The chest image of a bearded and long-haired Christ in a tricolor mandorla of blue, blue and white on a dark blue celestial background was preserved by the mosaic of the chapel of St. Matrona in the church of San Prisco in Capua Vetere (the first half of the 5th century) ^{[27, p.27]}. The solid golden halo of Christ, the silhouette of his figure in golden robes are edged with two rows of dark blue tesserae (Fig.19).

19. Christ in the mandorla. Mosaic of the Chapel of St. Matrons in the Church of San Prisco in Capua Vetere, V century. Image source: https://www.ancientcapua.com/worfgtkkress/wp-content/uploads/2013/08/56.jpg

In the mosaic of the triumphal arch of the Basilica of San Paolo fuori le Mura in Rome (V century), the composition of the upper tiers is all presented on a golden background (Fig.20). The apocalyptic motif here is combined with two fundamental themes of the early Christian monumental programs of Roman temples: the theme of the establishment and glorification of the Church and the theme of the glorification of martyrdom, which became an important factor for the spread and strengthening of Christianity in the era of persecution. Christ is depicted in a round mandorla located in the keystone of the arch in the upper tier, flanked by elongated images of symbolic beings accompanying the Glory of the Lord in the visions of the Old Testament prophets (Isaiah, Ezekiel)  and appearing in the vision of John the Theologian, telling about the end of time.   The apocalyptic motif is enhanced by trumpeting angels and images of elders in white robes.  The elders hold martyr crowns in their hands and worship Christ. In the lower case, on a bright blue background, the apostles Peter and Paul point to the scene in the upper case, which in the composition with Christ symbolically represents the Church of Christ as a "community of believers" - a community consisting of former Jews and Gentiles Christianized by the apostles ^{[29, p.90-95]}.   Of particular interest, however, in this composition is the image of Christ with the face of a stern, formidable Judge with a golden halo outlined by a wide dark blue contour outside and a thin white line inside, from which clearly highlighted shining rays radiate in all directions, cutting through the space of the mandorla and going beyond its boundaries (Fig. 20, 21). The image is chest-shaped, in a blue-blue mandorla, where the intensity of coloring increases  from light blue to dark blue as we approach the border of Mandorla — a technique that was used earlier in the mausoleum of St. Nicholas. Constance. The Mandorla is edged with a thin line of white tesserae separating it from the golden background.

20. The Triumphal arch in the Basilica of San Paolo Fuori le Mura in Rome.  Photo of the author.

Fig. 21. The image of Christ. A fragment of the mosaic of the Arc de Triomphe of San Paolo fuori le Mura in Rome. Photo of the author.

The closest iconographic sources of such representation are the image of Apollo Helios in the Roman floor mosaic in the El Jem Museum in Tunis (Fig. 3), the personification of the Sun in the Roman floor mosaic in Sparta (Fig. 4), the image of Christ Helios in the mausoleum of Julius under St. Peter's Basilica (Fig.2) and others like him.  The main difference is the representation of Christ in the image of a bearded, long—haired and stern Judge, and not in the image of a beardless Apollonian youth. In any case, it is clear that in such an image of the halo of Christ, the emphasis is deliberately placed on the iconography of the solar deity. The same motif is supported by the celestial color of the mandorla, against which the golden halo of Christ shines like the sun in the sky. 

The solar symbolism of the composition representing Christ in the keystone of the triumphal arch of San Paolo fuore le Mura, a chest image inscribed in a blue—blue mandola with rays cutting through it, is transformed in VI century monuments into a radiant chrysanthemum in a mandorla (Fig. 22). 

22. Transformation of the composition representing Christ with a halo of radiant solar type into a radiant chrysanthemum.

Examples of such a possible transformation, excluding an anthropomorphic image, but emphasizing the divine luminosity of the Lord, can be seen in the image of the triple chrysma in the mosaic decoration of the baptistery arch in Albengo, which V. N. Lazarev dated to the beginning of the VI century. ^{[27, p.27]}, in the image of the chrysma in the mandorla in the keystone of the triumphal arch of the apse and the arch of the presbytery of the church San Vitale in Ravenna, the mosaic decoration of which dates back to 546-547 ^{[27, p.44]}.

Fig.23. Mosaic of the apse of the Church of St. Cosmas and St. Damian in Rome, VI century. Photo of the author.

24. Christ and the Phoenix. A fragment of the mosaic of the apse of the Church of St. Cosmas and St. Damian in Rome, VI century. Photo of the author.

Figure 25. Christ. A fragment of the mosaic of the apse of the Church of St. Cosmas and St. Damian in Rome, VI century. Photo of the author.

Golden robes and a golden halo, bordered by a blue-white halo, we see in Christ in a mosaic of the VI century. in the apse of the Church of St. Nicholas. Kosmas and St. Damian in Rome (Fig. 23, 24, 25), where the entire composition is depicted against a bright blue sky, and the face of Christ is touched by bright orange flashes. These flashes, appearing on the face of the Lord, are reflected on the faces of the saints and apostles. They can also be perceived as a manifestation of the luminous nature of the Christian god ^[12].  They appear quite often in early Christian mosaics of the 5th–6th centuries. V. E. Suslenkov notes that in the works of the 5th century, "brick-red cubes are introduced into the letter of the faces, giving the faces a shade of spirituality and expression," which he rightly regards as a transfer of "glow" ^[12].  Thus, these orange flashes can be considered as another iconographic characteristic of the luminosity of Christ. In the same apse at the bottom there is an image of Christ in the form of a lamb standing on a mountain from which four rivers of paradise flow. The lamb has a white shimmering halo interspersed with golden tesserae and with a small cross inside it, directly above the lamb's head.

26 The lamb standing on the mountain from which the four rivers of Paradise flow. A fragment of the mosaic of the apse of the Church of St. Kosmas and St. Damian in Rome, VI century. Photo of the author.

In the mosaic of the apse of the Church of San Teodoro on the Palatine in Rome (VI century), Christ, surrounded by the apostles Peter and Paul, leading the martyrs to him, is depicted sitting on a blue-blue sphere, in brown and gold vestments, with a golden cross in his hands and with a transparent golden cross-shaped halo (Fig. 27, 28). The whole composition is depicted on a golden shimmering background. Above the head of Christ, the divine Right Hand, which is made of red and blue clouds, holds a laurel crown.

27. Mosaic of the apse of the Church of San Teodoro on the Palatine in Rome, VI century. Photo of the author.

Figure 28. Christ.  A fragment of the mosaic of the apse of the Church of San Teodoro on the Palatine in Rome, VI century. Photo of the author.

29. The triumphal arch of the Church of San Lorenzo fuore le Mura in Rome, VI century. Photo of the author.

A similar composition with the participation of the apostles  Peter and Paul, bringing the donator (Pope Pelagius), St. Lawrence, St. Hippolytus and St. Stephen to Christ, sitting on a blue sphere with a cross in his hands, preserved the triumphal arch of the Roman Basilica of San Lorenzo fuore le Mura (VI century). The composition is two-tiered, the background of the lower tier is emerald blue, dissolves into a shining light gold band, which, in turn, turns into a golden background of the second tier (Fig. 29). There are no red-blue clouds in this composition. The cross-shaped golden halo of Christ with double edging is decorated with precious stones of red, blue and white colors, the appearance of which in the decoration of the halo, apparently, was supposed to accentuate their divine ability to emit light (Fig. 30).

Figure 30. Christ. Fragment of the triumphal arch of the Church of San Lorenzo fuore le Mura in Rome, VI century. Photo of the author.

 The appearance of halos decorated with precious stones is often found in monuments of the VI century. He can be seen in the mosaics of Ravenna (the halo of Christ in the apse and in the medallion of the arch of the presbytery of the Church of San Vitale (Fig. 31), the halos of Christ in his images in the archbishop's chapel, in the Basilica of San Apollinare Nuovo, in the mosaics of the Arc de triomphe and the apse of the Ravenna church of San Michele in Affricisco (now in the Museum of Byzantine Culture in Berlin), in the image of Christ in the keystone of the triumphal arch in the church of St. Euphrasius in Porec, etc.).

Figure 31. Christ. A fragment of the mosaic of the apse of the Church of San Vitale in Ravenna, VI century. Photo of the author.

Figure 32. Christ. The Catacombs of Pontian. Rome. Image source: [Villepert, taf.257]

The abundance of gold and the richness of the mosaics of the Roman and Ravenna temples of the sixth century did not, however, cancel the use of more modest versions of the image of Christ, continuing the original tradition of wall painting of the catacombs.  In the catacombs of Pontian, we see a chest image of Christ (fig. 32), which is Villepert dates the border of the VI–VII centuries ^{[26, S.257]}. The background of the cross-shaped halo of the Savior is yellow-beige, surrounded by a double contour — thin white inside, wider brown outside. The cross of the halo is painted white and surrounded by a dark brown outline. Red highlights are traditionally visible on the face of Christ.

The image of the "Son of Man coming in the clouds", combined with solar symbols, is vividly represented in its own way by the mosaic of the apse of the Chapel of St. Nicholas. Venanzio and St. Domnio in the Lateran Baptistery (fig. 33, 34). The style of the two tiers of the composition is very different from each other, which suggests that the mosaic was made in two stages. M. A. Lidova considers the analysis of various points of view on this issue in her work, noting at the same time that none of them is generally accepted ^[30].  Nevertheless, the style of the mosaics of the upper tier, in our opinion, forces us to agree with the opinion of G. Mathieu ^[31] and V. Pace ^{[32, p. 219]} about the connection of these mosaics with Roman art of the early VI century and its late Antique prototypes, whereas the style of mosaics of the triumphal arch and the lower row of the apse, with the image of donors, saints and the Mother of God, tends already to the "asceticizing" trend in Roman painting of the VI–VII centuries.  In any case, since the chapel itself was built by order of Pope John IV, whose pontificate period falls on the 640s-642s, its mosaic decoration dates back to the VII century. The client of the chapel is depicted on the left in the lower part of the apse as a donor with a model of the temple in his hands. 

Fig.33. Mosaic of the apse of the Chapel of St. Venanzio and St. Domnio in the Lateran Baptistery, VII century. Photo of the author.

On the right, the composition closes with an image of another pope, whose identification varies. This may be the successor of John IV, Pope Theodore I (642-649), during whose pontificate the work on the decoration of the chapel could be continued. It may also be an image of Pope Hilary (461-468), the customer of the chapels of St. St. John the Evangelist and St. John the Baptist (not preserved) ^[30]. The long-haired, bearded Christ is depicted on a golden background, rising like the sun from red, blue and white clouds. His face and neck are touched with orange highlights.   The halo with a white border consists of two parts: the golden glow around the head turns into white, against which red-blue clouds are visible, which makes the halo seem transparent. The nimbus of Christ is not cross-shaped, which was also found in Roman monuments of the VI century (mosaic of the apse of the Basilica of St. Cosmas and St. Damian in Rome), but it seems very unusual for the representation of Christ in subsequent times. Two angels in blue and white robes with the same transparent halos and orange highlights on their faces flank the chest image of Christ, like the imperial guard.

34. The image of Christ in the clouds. A fragment of the mosaic of the apse of the Chapel of St. Venanzio and St. Domnio in the Lateran Baptistery, VII century. Photo of the author.

The iconography of the apse as a whole resembles the "reworked" theme of the "Ascension" ^[30], although it certainly has a complex program that includes various motifs, including the motif of the Second Coming (Matthew 24:27-31), and "Christ is the sun of truth" (Malachi (4-2): "And for you, Those who are in awe of My name, the Sun of righteousness will rise and healing in Its rays, and you will come out and leap like fat calves." The last text perfectly correlates with the purpose of the building, with the idea of human transformation as a result of the sacrament of Baptism.

This theme of the Christ-sun, the "sun of truth" or the "true sun" is supported by a number of monumental compositions of subsequent centuries in Rome, Ravenna and the Lazio region, where Christ in golden robes or with a golden halo appears against a background of blue skies like the sun rising against a background of red-blue shining clouds. Such compositions begin to represent the theme of the Second Coming, according to the text of the Gospel of Matthew (Matthew 24:27-31): "for as lightning comes from the east and is visible even to the west, so will be the coming of the Son of Man ... coming on the clouds of heaven with great power and glory," although a full-fledged iconography of this scene will be formed much later, it will include a number of important iconographic characteristics ^{[33, 34]}, which are still missing in the monuments of the V–VII centuries.  Nevertheless, the monumental compositions decorating the apses and triumphal arches of Christian churches of the 5th–7th centuries initially demonstrate a complex "synthetic" structure that includes various texts and meanings in one pictorial field.

The solar symbolism has been conveyed for centuries by the very color scheme of this kind of scenery, where blue is combined with gold, white, red and sky blue. This is the mosaic of the apse of the Basilica of St. Cosmas and St. Damian in Rome (VI century), mosaics of the apses of the Church of St. Cecilia (IX century) and the Church of St. Prassede (IX century.) in Rome, the fresco of the apse of the church of St. Sylvester in Tivoli (XII century.), the mosaic of the apse of the Basilica of San Giovanni in Laterano, where the mosaic of the XIII century was reconstructed in the XIX century. and many others.  A representation of a snow-white lamb with a golden halo against a dark blue starry sky in the vault of the Vima church of San Vitale in Ravenna (VI century), a lamb on a golden background with a blue halo in the vault of the chapel of John the Evangelist in the Lateran Baptistery (V century), a golden cross or golden chrysanthemum shining on a bright blue background, sometimes studded with stars, as in the mosaic of the vault of the mausoleum of Galla Placidia (V century), in the mosaic of the triumphal arch of the church of San Lorenzo fuore le Mura in Rome (VI century), in the mosaic of the vault of the baptistery in Naples (V century), etc. They refer to the same solar characteristics of the divine presence, the image of the sun rising from the clouds or from the blue of the sky. The golden background, representing the transcendent kingdom of Light, at the same time, not only demonstrates the light nature, but symbolically designates this other, invisible to human eyes, divine space, from which the Lord reveals himself to the earthly world among the clouds in the sky.    This light can be depicted as uniform or flickering, interspersed with tesserae of other colors.  At the same time, in all temple compositions of the V–VII centuries. Christ is represented with a halo, and his appearance is quite diverse.  The variants of the representation of the halo of Christ for the monuments we have considered are presented in Table 2.

Table 2. Variants of the representation of the halo in the depiction of Christ in Western European temple decorations of the IV–VIII centuries.  

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In the monuments of Rome in the IV century. two types of halos surrounding the face of Christ can be distinguished. The radiant variant (type A) is represented by a mosaic depicting Christ-Helios in the Julius Mausoleum under St. Peter's Basilica, the second variant (type B) is presented in three subtypes (Table 1; Table 2).  Two of them are found, as a rule, in the painting of catacombs:  subtype B1 is a transparent halo with two—tone edging - red on the outside and brown or blue on the inside; subtype  B2 represents images of Christ, where a halo of simple yellow color with dark edging is used, inside which a thin white outline is read. The third option is found in the mosaics of the mausoleum of St. Nicholas. Constantia, where the image of Christ is surrounded by a halo with a smooth transition from white to sky blue and blue, without edging (subtype B3). 

In the temple monumental decoration  5th century in the mosaic of the central nave of Santa Maria Maggiore ("The Hospitality of Abraham")  around the faces of the three men representing the Trinity, the halo looks like a white glow on a golden background (C1), or blue-white on blue, reminiscent of the techniques of the IV century, whereas when depicting Christ in the scene of the "Adoration of the Magi" in the Arc de Triomphe, it becomes golden with white edging and a small sign of the cross inside (C3-2). Among the considered monuments, four main variants of the representation of the halo of Christ can be distinguished: C1 — a simple white glow on a golden background, C2 — a simple golden halo without edging, C3 — a simple golden halo with edging of various types: C3-1 — with white edging; C3-3 — with dark edging, C3-4 is a golden halo with a shimmering effect due to the addition of blue tesserae (Baptistery of Naples). Of particular note is the mosaic of the Chapel of San Aquilino in San Lorenzo Maggiore in Milan with the image of Christ with the apostles, the dating of which has long varied between the IV-VI centuries, but since the 1970s, as S. P. Zaigraikina notes in his dissertation ("Artistic features of mosaics in the chapels of Sant'aquilino and San Vittore in Whose dOro in Milan: problems of the evolution of style in the art of the 5th century", 2015, pp. 33-36, 170), it is customary to date all parts of the mosaic of the chapel to the boundary of the IV–V centuries, or the beginning of the 5th century. The halo of the Apollonian beardless Christ attracts attention (Fig. 15). It is golden in color with white edging, inside it the letters "alpha", "omega" and the sign of the radiant chrysanthemum behind the head are lined with white tesserae, which allows it to be classified as type A (subtype A2).  The same type can be attributed to the halo of Christ in the Arc de Triomphe of San Paolo fuore le Mura in Rome (subtype A1).

In the monuments of the VI century, a simple golden halo with a white or white-blue shining edging is preserved (the apse of the Church of St. Cosmas and St. Damian in Rome), which can be attributed to type C3. In the same apse, in the white-gold shimmering halo of the lamb, there is a small sign of the cross, which corresponds to the C3-2 subtype. The tradition of catacomb painting of the IV century continues and is complemented by a strict cross-shaped halo with a cross having three color options. It can have a color similar to the background color of the halo, dark, or white, depicted on a solid yellow background with a double contour, wide brown outside and thin white inside, as in the catacombs of Generose (Fig. 11) or in the catacombs of Pontian (Fig. 32), where the image of Christ has a yellow halo with a white cross (type D). At this time, it should be noted that Christ has a cross-shaped halo in the form of a golden cross decorated with precious stones on a golden background (San Lorenzo fuore le Mura, triumphal arch; apse and arch of the presbytery of the church of San Vitale in Ravenna), which can be attributed to type E1; a golden cross on a golden background with dark edging without precious stones (type E2), possibly with a transparency effect (mosaic of the apse of San Teodoro on the Palatine in Rome).

In the Roman monuments of the seventh century, it should be noted the original image of Christ with a transparent golden halo with white edging (C3-1), which is located in the apse of the chapel of the Lateran Baptistery, dedicated to St. Nicholas. Venanzio and St. Domnio (fig.34). The halo is not cross-shaped, consists of two colors, a golden glow surrounds the face of Christ, and then turns into white, against which, piercing the contour, red and blue clouds are visible. In this case, different characteristics presented in individual monuments of the VI century are combined in one monument.

In the monumental decorations of the Western European Christian churches of the VIII century, where the image of Christ has been preserved, the cross-shaped halo is depicted, as a rule, according to type D. It has a solid yellow background with double edging, a dark wide line on the outside and a thin white one on the inside.  These images are found in the basilicas of Rome (frescoes of the church of Santa Maria Antiqua and the church of Santa Saba), in the Cividale del Friuli (fresco in Tempietto Lombardo), the image of Christ in mandorla in the murals of the church of Santa Maria foris portas in Castelseprio can be attributed to the same type. The type of cross can be different.

Fig. 35. The scene "Carrying the cross". A fragment of a fresco in the church of Santa Maria Antiqua in Rome, VIII century. Photo of the author.

36. Christ in the mandorla. A fragment of the painting of the church of Santa Maria foris Portas in Castelseprio. Photo of the author.

It can be a cross made up of thin lines lying side by side, brown and white, as in the fragment of the fresco "Carrying the Cross" in the church of Santa Maria Antiqua in Rome (Fig. 35).  The cross, which matches the background of the halo of Christ in color (fresco in the church of Santa Maria foris portas in Castelseprio, fragment of the scene "Crucifixion of Christ" from the church of Santa Maria Antiqua in Rome), can be highlighted with a shade lighter than the background and a thin white outline (Fig. 36) or double edging, outside brown and thinner, white, inside (fig. 37). 

Figure 37. Christ. Fragment of the fresco "Crucifixion of Christ" from the church of Santa Maria Antiqua, VIII century. Photo of the author.

38. Fragment of the scene "Healing of a paralytic" in the wall painting of the Church of Santa Saba in Rome, VIII century. Photo of the author.

  The cross, which matches in color and shade with the background color of the halo, can be highlighted with a brown or brown-white double contour, as demonstrated by the halos of Christ from the frescoes of the church   Santa Saba in Rome (fig. 38, 39).   At the same time, the halo of Christ from the composition "Healing of the paralytic" in the church of Santa Saba has an additional white stripe in the middle of its horizontal part (Fig.38), and therefore can be attributed to a separate group.

Figure 39. Christ. Fragment of the fresco of the VIII century. San Saba, Oratorio, Rome.   Image source: ^{[35, p.74, fig.30]}

In the representation of the image of Christ in the Chapel of the Dukes of Friuli (Tempietto Lombardo)  The halo can be attributed to the D2 subtype. He continues and develops the most ancient tradition, presenting a cross on a yellow background replacing gold, surrounded by a double white-brown border. However, the cross of the halo in this case is enriched with the image of precious stones adorning the golden halos of Christ VI. The brown outline surrounding it is studded with pearls, and remnants of jewelry can also be seen in the sleeves of the cross (Fig. 40).

Fig. 40. Christ. Fragment of a fresco by Tempietto Lombardo in Cividale del Friuli, VIII century. Photo of the author.

In the Western European temple monumental decorations of the 5th–8th centuries, one can see images of Christ, the lamb or the chrysanthemum enclosed in a round mandorla symbolizing radiance  Glory of the Lord (wooden panel of the doors of the Church of St. Sabina in Rome, triumphal arch in the church of San Paolo fuore le Mura, golden chrysanthemum at the end of the triumphal arch of the Basilica of San Lorenzo fuore le Mura (fig. 41), medallion with the image of Christ in the arch in the church of San Vitale (Fig. 42), medallions with the image of Christ in the Archbishop's chapel in Ravenna, etc.).

41. The chrysanthemum in the mandorla. Mosaic of the Arc de Triomphe in the Church of San Lorenzo Maggiore in Rome, VI century. Photo of the author.

In the example given from the church of San Vitale (Fig. 42), the multilayer mandorla of Christ includes all the colors of the rainbow, thus conveying the fullness and diversity of the components of divine light. This version of the representation of the luminosity of Christ will receive a much larger development in the temple decorations of subsequent eras.

42. The medallion with the image of Christ, the arch of the presbytery in the church of San Vitale in Ravenna, VI century. Photo of the author.

 In the iconographic repertoire of Christian art of various centuries, there is another image that is directly related to the representation of the luminous nature of Christ. This is the image of the phoenix bird, which had a solar nature since pre-Christian times, and in Christian programs directly began to symbolize Christ ^{[36, p.97-113]}.  The texts of early Christian writers identify the most important properties of this bird, likening it to Christ, and it has been associated with the sun since the time of its pagan past (the Egyptian bird Benu and ancient descriptions of the Phoenix) ^{[36, p.3-18, 35-63]}.

 In the Epistle to the Corinthians of Pope Clement I, the author considers the resurrection of the Phoenix as a sign of the subsequent resurrection in the flesh awaiting believers ^[37], but the "Physiologist" identifies the bird with Christ and His resurrection. The text of the Physiologist explicitly says: "The Phoenix assumes the image of our Lord" ^[38].

In ancient art, the Phoenix is also depicted with a radiant halo, its image can be seen on the floor Roman mosaic in the Phoenix House of Antioch on the Orontes (V century) ^{[36, p.78, fig.5.1]} from the collection of the Louvre, in the same form it appears in the mosaic of the vault of the baptistery of the Naples Duomo (V century). In the programs of the apses of the temples of Rome and Lazio, a phoenix with a shining halo, sitting on a palm tree, accompanies the appearance of Christ, repeating with golden plumage the golden radiance of the Lord's robes.  This composition can be seen, for example, in the mosaic of the Church of St. Cosmas and St. Damian (VI century) (fig. 24), then in the apses of the Roman churches of St. Cecilia and St. It is repeated in the church of St. Sylvester in Tivoli (XII century), and in the mosaic of the apse of San Giovanni in Laterano in Rome (XIII century).

 However, in the program of the mausoleum of Galla Placidia in Ravenna (V century), the luminous bird is located under the very arch on four sides of the representation of the golden cross in the starry heavens, representing the appearance of the Lord (Fig. 43).

43. Mosaic of the mausoleum of Galla Placidia, Ravenna, V century. Photo by the author.

The shining bird (Fig. 44), which E. K. Redin calls a "shell with an eagle's head" and considers as an ancient heritage, as a decorative element of niche decoration, having the appearance of a shell ^{[28, p.57]}, in our opinion, represents precisely the phoenix, which was directly connected in the Christian period with the representation of the martyrdom which acquires a particularly important meaning in the program of the mausoleum of Galla Placidia. This allows us to consider the entire iconographic program of the monument  as a single whole, united by the image of this divine light descending into the world in the form of a luminous bird symbolizing Christ. This issue was discussed in detail by the author in the report "Iconographic program of the Mausoleum of Galla Placidia in Ravenna: on the question of interpretation" at the VI International Scientific Conference "Biblical and Liturgical themes and images in the art of East and West: dialogue of cultures, tradition and modernity" on December 22-23, 2021. (Moscow, RGGU, MDA) and will be presented in a separate article.  Turning to the image of the phoenix, it should be noted that its representation is gradually transformed in Ravenna programs from the image of a luminous bird (Mausoleum of Galla Placidia, San Apollinare Nuovo) to the image of diverging light rays in mosaicsSan Vitale and San Apollinare in Class. In the same capacity, the image of the radiant phoenix-"shell" is then moved to later temple programs, the representation of the idea of the luminosity of Christ, in which it will be considered in the future.

44. The image of the phoenix. Mosaic of the mausoleum of Galla Placidia, Ravenna, V century. Photo by the author.

Thus, based on the material of the considered Western European monuments of the IV–VIII centuries, the following techniques can be distinguished, used to represent the luminosity of the divine nature of Christ in the temple decoration:

· The choice of mosaic material, perceived as imitation of precious stones emitting light.

The Apollo-like face of Christ.

· Color symbols: white, gold, sky blue, blue, red.

· Gold background.

· The golden robes of Christ.

· Orange flashes on the face of the Savior, the apostles and the saints.

· White robes of the Savior, angels, apostles, saints.

· Golden chrysanthemum on a blue background or a starry sky background.

· Mandorla.

· Inscriptions ("L"), implying Lux and Lex; or the full text "Ego sum Rex gloriae" (text in the book that Christ held in the mosaics of the nave of San Apollinare Nuovo in Ravenna, a lost fragment).

· The chest image of Christ in the clouds as "Christ is the true Sun", "Christ is the Sun of truth".

· Colored highlights on clouds as reflections of the rising "Christ — the Sun of Truth".

· A snow-white lamb on a golden background or on the background of a starry sky with a blue or golden halo.

· Various types of Christ's nimbus (Table 2).

· A phoenix with a radiant halo, in the form of a bird sitting alone or on a palm tree.

· A phoenix emitting rays of light along a segment of a circle (mausoleum of Galla Placidia, San Apollinare Nuovo, Ravenna).

The classification of variants of the representation of Christ's halos presented in Tables 1 and 2 and the change in their characteristics during the period under review show that the greatest variety of variants occurred in the 500-650's, when the largest number of variants of the image of Christ's halo were used simultaneously. The use of fresco technique is preserved mainly in catacomb painting, and the decoration of ground temple buildings shines with gold mosaics, the golden cross of the Savior's halo is very often decorated with the image of precious stones. It was, however, a very difficult time for Rome and its legacy. Famine, endless wars, changes of rulers, diseases and earthquakes steadily led to decline and desolation. However, the positions of the church and the bishop of Rome were strengthened at the same time, the construction and decoration of temples did not stop, but only amazed with the abundance of gold and the radiance of colored glass. Gradually, the wealth of Rome is melting away and in the monuments of the VIII century. expensive mosaic technique becomes inaccessible and is replaced by a fresco, the "gold" of the halos now turns yellow and beige, and "precious stones" are depicted with a brush.  In general, the classification picture, representing a change in iconographic and typological characteristics associated with the representation of the halo of Christ and the luminosity of his divine nature in the monumental temple decoration, not only allows us to identify the characteristic features of the visual language of Western European religious art of the period under consideration, but also reflects to a certain extent the historical situation, which may be useful in clarifying the dating of monuments.