…vera fidelium relatio…

Anotace: The author deals with the sources that the oldest Czech chronicler, the Dean of the Prague Chapter Cosmas († 1125) used for his interpretation of older Czech history and the personality of the third Prague bishop Thiddag (998–1017). On the basis of an analysis of Cosmas’s text, the author concluded that the chronicler had, in addition to the Imperial annals, a catalogue of Prague bishops, incomplete reports of the succession of Czech rulers, several annalistic records of Czech history, and an oral tradition. The lack of information in some places was replaced by his rhetorical abilities. As for Bishop Thiddag, Cosmas tells about his election and enthronement, then about his death on June 11, 1017. It is apparent that Cosmas did not know much about the third bishop of Prague and the events that took place under his office, so he helped out the usual rhetorical topoi.