Who was Isabella of Brienne and how did her marriage affect Frederick II’s claim to Jerusalem?

Isabella II (also known as Yolande of Brienne) was the queen of the kingdom of Jerusalem and the daughter of John of Brienne. In 1225, she married the Holy Roman emperor Frederick II, a union encouraged by Pope Honorius III in the hope that it would bind the emperor to the cause of the Crusades.1

This marriage was pivotal to Frederick’s political ambitions, as it provided him with a legal claim to the throne of Jerusalem through his wife. Immediately following the wedding, Frederick demanded sovereign rights in the kingdom, which he asserted in Isabella’s name. This move created immediate friction with his father-in-law, John of Brienne, who had been acting as regent and was reluctant to relinquish his position.12

Even after Isabella died in 1228 following the birth of their son, Conrad, Frederick maintained his claim to the throne. He eventually traveled to the Holy Land and, through diplomatic negotiations, secured Jerusalem, Bethlehem, and Nazareth, crowning himself king of Jerusalem in 1229.12