William II of Agen (also known as Guillaume d'Agen) was the Latin Patriarch of Jerusalem in 1261–70. Among other things, he was tasked by Pope Urban IV in 1263 by the papal bull Exultavit cor nostrum to investigate the legitimacy of an alleged ambassador with the Mongol Empire, John the Hungarian.
References
edit- Peter Jackson, Mongols and the West, p. 166