Her legal case was solid, resting on the proximity of blood to the king, but she was rejected by the High Court of Jerusalem in favor of Hugh III of Cyprus.
In addition to the throne of Cyprus, Hugh III claimed the regency of the Kingdom of Jerusalem, and the High Court was prepared to accept him.
[5] But when he sailed in May 1268 to Acre,[5] the capital of what remained of that Crusader state, he found his claim challenged by his aunt Maria,[4] who was then in her forties.
[9][10] She asserted that the regency should belong to her because she was, by one degree, more closely related to the king of Jerusalem, Conrad III,[5] and the only surviving grandchild of Isabella I.
It appears that the High Court recognized the superiority of Maria's claim and used her absence to justify awarding the regency to Hugh,[12] arguing that she was in default.
[5] In reality, Hugh was preferable because he had experience in government and his Cypriot troops could contribute to the defense of the dwindling kingdom against the Egyptian sultan Baibars.
[14] She demanded that she be crowned by the Latin patriarch of Jerusalem, William of Agen,[14][15] but he "scornfully dismissed" her claim and "considered it worthless".
[20] The papal curia knew that her claim was better than Hugh's,[21] but the cardinal bishop of Albano, Bonaventure, explained that only the barons of Jerusalem had the power to decide their monarch.
[21] In March 1277, Maria sold her claim to Charles for annual payments of 4,000 livres tournois and 10,000 Saracen bezants from Acre.
[24] Hugh's son Henry II regained Acre in 1285,[25] but when the city fell to the Egyptian sultan Al Asraf Khalil in 1291, the Kingdom of Jerusalem was permanently destroyed.