Ivan Asen III of Bulgaria

Ivan Asen III (c. 1259–1303), son of Tsar Mitso Asen and a daughter of Ivan Asen II, claimed Bulgaria with Byzantine backing. In 1277 or 1278 Michael VIII Palaiologos made him despotēs and married him to his daughter Irene Palaiologina.

While Ivaylo's rebels were blockaded at Silistra, a Byzantine army besieged Tarnovo; hearing a rumour of Ivaylo's death, the nobles surrendered and accepted Ivan Asen as emperor in 1279. He married his sister Maria to George Terter. Ivaylo returned and routed two relief armies; in 1280 the tsar fled the capital with the palace treasure and sailed to Constantinople, where he sought Nogai Khan's aid in vain. He died on his Troad estates in 1303.