Yolande of Brienne (1212 - 1228), also known as Yolanda or Isabella II, inherited the Kingdom of Jerusalem as an infant in 1212.
She was the daughter of John of Brienne and Maria of Montferrat. Because John did not have a direct claim on the throne, Yolande succeeded Maria upon Maria's death in 1212. John ruled as regent until 1225, when she married Frederick II, Holy Roman Emperor. Frederick claimed the kingdom for himself; when Yolande died after giving birth to their son Conrad in 1228, Frederick ruled as regent, settling a truce with the Muslims in 1229 during the Sixth Crusade.
See also: Other young rulers