The paper deals with the story of Marcantonio Trissino, the grandson of Giangiorgio Trissino, the famous man of letters and humanist. In the year 1583 Marcantonio, abruptily and amazingly, killed Giulio Cesare Trissino outside Vicenza's dome while he was surrounded and protected by numerous friends and followers. Giulio Cesare Trissino was suspected by the public opinion being the mandant of Ciro Trissino's murder, the father of Marcantonio, killed in february 1576 in his palladian villa located in Cornedo, a Vicentine village, by a group of goons, masked and dressed in black suits. During the trial instructed in Padua by appointment of the Counsel of ten, Marcantonio Trissino defended his violent behavior advocating that his mind was run o...