In 1390 the Ottoman sultan annexed the beyliks of western Anatolia: the beylik of Sarukhan was annexed, as were Menteshe and Aydın, whose rulers were allowed to retire to estates, while Yakub II of Germiyan was thrown in prison. Bayezid then moved to besiege the Karamanid capital of Konya. The Karamanids sent to Kadi Burhan al-Din for assistance, which induced Bayezid to abandon Konya and conclude a treaty leaving to the Karamanids the territories beyond the Çarşamba River.[3][4][5] In the meantime, Bayezid's ally Süleyman Pasha had turned against him, fearing for his own fate, and concluded an alliance with Burhan al-Din.