Abstract: The article examines the issue of the genealogical classification preserved in the copies of Medieval texts. For its understanding the authors propose an approach based on the use of the theory of fuzzy sets. This approach utilizes the matrix of the fuzzy preference relation, which is founded on the pairwise comparison of the lists with each other. Each element of this matrix is the summation of its components, whose value is determined by the end set of different value factors (types of lection). These factors are considered in their total sum in the form of weight coefficients, which are determined through expert means. In order to eliminate the unavoidable subjectivity in evaluating them, the authors of this work developed an indirect method of expertise. The aim of the proposed method lies in that the given factors are compared pairwise in their value with each other. This way the initial complex problem is substituted by the entirety of more simple ones. Meanwhile the experts operate not with quantitative, but qualitative evaluations. The proposed new approach of expert evaluation allows in a formal way to assess the value of one or another discrepancy in the text. Thus the use of the proposed method plays a key role in the fuzzy classification of the list of Medieval compositions (establishing a genealogical stemming). The use of the examined method is illustrated on a specific example of discrepancy typology.