Hosius was appointed royal secretary. In that position, he had the entire confidence of King Sigismund, who bestowed various ecclesiastical benefices upon him as reward for his faithful services. In 1543, Hosius was ordained priest. King Sigismund died in 1548, but before his death, he had instructed his son and successor, Sigismund II, to nominate Hosius for the next vacant episcopal see.

Hosius was nominated for the See of Chelmno in 1549. He had not sought that dignity and