After the emperor of the Empire of Trebizond refused to pay tribute and made an alliance with the Akkoyunlu Mehmed led a campaign against Trebizond by land and sea. He led a sizable army from Bursa by land and the Ottoman navy by sea, first to Sinope, joining forces with Ismail's brother Ahmed (the Red). He captured Sinope and ended the official reign of the Jandarid dynasty. After a siege of more than 32 days, Trebizond and the emperor surrendered and the Empire came to an end.