and Hulagu decided it was wise to withdraw to Tabriz to await the resolution of this conflict. On 23 Rabiʿ II 658/7 April 1260, Mayafaraqin fell to Hulagu's forces, presumably during their retreat towards Ahlat and Tabriz, leaving Mardin and Hisn Kayfa as the only cities outside his control in the Jazira. Mardin was captured by the end of 1260, but Hisn Kayfa appears to have escaped a concerted assault because it controlled only a minor trade route and could simply be bypassed. Nevertheless, it seems that al-Muwaḥḥid decided to submit to being a Mongol vassal at about this time. While most of the Diyar Bakr came under direct control of the Mongol governor or Mosul, both Ayyubid Hisn Kayfa and Artukid Mardin were allowed to remain as vassal states. By the Mamluk Baybars was in power in Egypt, and represented the primary force opposing the Mongols, now led by Hulagu's son Abaqa Khan. Baybars sent two eunuchs as emissaries to al-Muwaḥḥid to try to persuade him to abandon the Mongols, and apparently the emir of Hisn Kayfa agreed. However, the envoys were caught by a local Mongol commander as they attempted to carry al-Muwaḥḥid's reply to Baybars. Abaqa had the envoys executed, and al-Muwaḥḥid was banished to the Ilkhanate court for seven years. By al-Muwaḥḥid had returned as the nominal ruler of Hisn Kayfa, where he remained until his death, variously reported as having occurred in or . Mongol rule of the region continued until 1335, and this badly damaged both trade and agriculture, which had been the sources of the region's prosperity. The impact was felt hardest between 1260 and 1315, and traders essentially avoided the region because of ongoing war between Mamluk and Mongol forces. In 1315, the Il-Khanate and the Mamluks signed a treaty and trade restarted. This proved to be a boon for Hisn Kayfa. The previous primary routes across the region—through Cizre and Nusaybin, and through Mayafaraqin and Amida (Diyarbakır)—both failed to attract many traders, and a new route from Iran to Aleppo through Siirt, Hisn Kayfa and Mardin took their place. The economy of the region gradually shrank during the 14th and early 15th centuries, according to historian Thomas Alexander Sinclair, but this probably did not cause any population decline in the cities of Mardin or Hisn Kayfa, where building continued uninterrupted. Several other cities in the region, such as Mayafaraqin, Arzan, Nusaybin