Using the example of Catherine of Siena († 1380), one of the possible motivations of writing down the legend is followed in the study, and the exploitability of Catherine for the promotion and official confirmation of the Dominican Third Order (1405). In the documents promoting the Third Order, her as-yet uncanonised holy example has an important place as a model for a Tertiary. This fact, however, is in contradiction with the evident "inappropriateness" of Catherine´s life as a real model for Tertiaries, for her extreme practices, exceeding the limits of the Rule. The real function and importance of St. Catherine´s model in the life of the Tertiaries should therefore be complementary viewed in the context of the legend of her repetant successor Mary of Venice, whose author is a great suppporter of Catherine´s holiness and Third Order, Tommaso da Siena. Whereas Catherine served as an ideal, Marie should be an example for practical imitation for Tertiaries., Kateřina Ptáčková., and Obsahuje poznámky pod čarou