The author deals with the diplomatic mission of canon and later cardinal Otto Truchsess to Poland in 1542. This was associated with repeated attempts to convene an ecumenical council - this time to Trento on November 1, 1542. Otto Truchsess was appointed papal legate, with instructions to forward the invitation to participate in the intended council to the Reichstag in Nuremberg and the Polish royal court in Krakow. The papal legate arrived in Krakow on October 12 and left the city on November 8, 1542. It failed: he received only a vague promise that the Polish king would send a delegation to the council. However, this did not stop him from having a brilliant church career.