About Sigismund Kraljević Ostojić
Ishak-bey Kraloglu From Wikipedia, the free encyclopedia Ishak-bey Kraloglu or Sigismund of Bosnia (Bosnian: Ishak-beg Kraljević/Исхак-бег Краљевић, Sigismund Kotromanić/Сигисмунд Котроманић) was one of the last known members of the House of Kotromanić.
Sigismund was the son of King Stephen Thomas of Bosnia by his second wife, Catherine of St Sava, the daughter of Stephen, Duke of St Sava. The year of his birth is unknown; it has been suggested that he was between 12 and 14 at the moment of the fall of the Kingdom of Bosnia in 1463 AD, but it has also been suggested that he was only seven. He was raised as a Roman Catholic. In 1461, Sigismund's father died, leaving the crown to his son from his first marriage, Stephen Tomašević. Sigismund and his younger sister Catherine continued to live with their mother at the court of his older half-brother and half-sister-in-law, Mary of Serbia. Life in Ottoman Empire
Two years later, the Kingdom of Bosnia was conquered by Mehmed the Conqueror. Sigismund's half-brother, King Stephen Tomašević, was executed, along with their uncle Radivoj and cousin Tvrtko. Sigismund's mother fled to the Adriatic coast and then to Rome, having left his father's sword in the Republic of Ragusa with instructions to preserve it for Sigismund. However, Sigismund and his sister were taken to Istanbul, where they converted to Islam. Sigismund then became known as Ishak-bey Kraloglu (kraloglu being the Turkish word for a king's son). In 1478, Queen Catherine died having left a will in which she had named Ishak-bey the rightful heir of the Bosnian crown if he converted to Christianity. Ishak-bey never did, remaining a Muslim for the rest of his life. Mehmed the Conqueror was very fond of Ishak-bey, often invited him to dinners and made him sanjak-bey of Bolu. Ishak-bey probably died in Bolu. Europäische Stammtafeln claims that he had issue but does not give any information about them.