The article is devoted to the figure of the Archbishop of Lviv, Jan Rzeszowski (1345/46-1436), whose family gained a high nobility status after receiving the Rzeszów estates from King Casimir the Great in 1354. Rzeszowski's career began thanks to his father, an influential adviser to Casimir the Great. He studied canon law in Padua and performed important church functions in Kraków. Only when he was about 60 years old did he appear on the public scene, becoming Archbishop of Lviv in 1414. Despite his advanced age, he led an active lifestyle, accompanying the king on his travels and supporting his controversial decisions. As legate of the Council of Constance, he led a Christianization mission in Samogitia. Under his rule, Catholicism in Russia was strengthened and the metropolitan's position in the church hierarchy increased. He managed a significant part of the family estate and died in 1436, being buried in a monastery on Mount Łysieć in the Świętokrzyskie Mountains. Archbishop Jan Rzeszowski was a typical church dignitary of his time, but devoid of the typical mistakes of this social class.