Ishak of Karaman was a bey of the Karamanids, a Turkish principality in Anatolia in the 15th century.
His mother was Turkish concubine, who Ibrahim later ordered to kill without Ishak's knowledge.
When he tried to march to his capital Konya, he learned that his younger brother Pir Ahmet had put a claim on the throne.
The help of Uzun Hasan, the sultan of Akkoyunlu (White Sheep) Turkmens enabled him to ascend to the throne, albeit for a short reign.
Because, Pir Ahmet appealed to Ottoman sultan Mehmet II for help.