Milan Šimek Pius II. a utrakvismus Pius II. and utraquism Based on sources work - out, the thesis aims the description and analysis of the attitude alternation of Enea Sylvio Piccolomini - Pius II to the utraquism. The conclusions stress the postulate that Pius II. did not change that attitude, but just did not succed in quelling the utraquist movement. In the sense of political background that finally led to fatal dissention among both leaders, king Jiří of Poděbrady and pope Pius II.