Sibylla, Queen of Jerusalem

Sibylla was the eldest daughter of King Amalric and became heir presumptive when her younger brother Baldwin IV took the throne at thirteen and promptly contracted leprosy. The regent married her to William Longsword of Montferrat in 1176, but he died within a year, leaving her pregnant with a son, Baldwin, and holding the County of Jaffa and Ascalon. Her brother arranged her second marriage to Guy of Lusignan in 1180, likely to block a coup, but the match split the nobility and Baldwin IV grew so disillusioned with Guy that he crowned Sibylla's son co-king to bar Guy from power. When Baldwin V died in 1186, Sibylla seized the throne against the regent's ambitions, agreed to annul her marriage, then remarried Guy the moment she was crowned and placed the crown on his head herself. Saladin invaded the fractured kingdom in 1187 and reduced it to the single city of Tyre after Guy's capture at Hattin; Sibylla secured his release, but in 1190 she and her daughters died of epidemic during the siege of Acre.