In Ishaq's absence, 'Izz ad-Din 'Aibag, Emir of Amadiya, seized the city, and an attack by Abd Allah, Emir of Mayyafariqin, was repelled. Baibars, Sultan of Egypt, refused to provide an army to the sons of Badr al-Din against the Mongols, but they were permitted to accompany Caliph Al-Mustansir on his campaign to reconquer Baghdad from the Mongols. The three brothers marched with the caliph's campaign until they split at Al-Rahba, and travelled to Sinjar, where Ali and Ishaq briefly remained whilst Ismail continued onwards to Mosul, however, the two brothers abandoned Sinjar and Jazirat Ibn ʿUmar to the Mongols, and returned to Egypt upon learning of the caliph's death and defeat in November. Mosul was sacked and Ismail was killed by a Mongol army after a siege from November to July/August 1262. After the sack of Mosul, the Mongol army led by Samdaghu besieged Jazirat Ibn ʿUmar until the summer of 1263; the siege was lifted and the city spared when the Nestorian bishop Henan Isho claimed to have knowledge of chrysopoeia, and offered to render his services. Jemal ad-Din Gulbag was appointed to govern Jazirat Ibn ʿUmar, but he was later executed for conspiring with the city's former ruler Ishaq, and was replaced by Henan Isho, who was also executed in 1268 following accusations of impropriety.