In church folksongs of Orthodox Russians, Friday appears in two forms. In the songs entitled “Friday”, the day appears in a personified form as Friday Woman (Piatnica). In the Russian church folksongs and prose texts which are called “On the twelve Fridays”, the day appears in an entirely different role. The Russian cultic veneration of the twelve Fridays can be traced back to the apocryphal writing “Sage of the Twelve Fridays” attributed to St. Clemens, a Roman. The apocryphal “Sage of the Twelve Fridays” of St. Clemens, which was rooted in a Roman Catholic religious-cultural background, was well-known throughout Europe. Variants of the texts of the Clemens-group appear in French, Provencal, Latin, Greek, German, Svabian in Hungary, Italian, English and Hungarian languages. Howewer, the legend of the twelve Fridays exists in another type as well. This is the Eleftherios-group. The group is named so because in these versions the list of the twelve Fridays is preceded by an introductory part, which is about the religious dispute between Eleftherios, a Christian and Terasios, a Jew.