Stjepan was born into the
Kosača family in 1456. He was third and youngest son of
Herceg Stjepan Vukčić, at the time most powerful
Bosnian noblemen. Stjepan's half-siblings from his father's first marriage included
Queen Katarina, wife of
King Stjepan Tomaš,
Vladislav Hercegović, and
Vlatko Hercegović, their father's successor. Stjepan's family belonged to the
Bosnian Church, but were "shaky Christians" like most of their countrymen. His half-sister, Catherine, converted to Roman Catholicism upon marriage and became pious follower of the church. Stjepan himself left Novi and departed for Constantinople in early 1474, at the latest, where he adopted Islam and changed his name to Ahmed. ==Career==