[2] It is very possible that in the spirit of the customs of the time, his brother Sandalj Hranić sent him to the sultan's court as a political and diplomatic move as a sign of loyalty to the emperor.

Ishak was appointed ruler by Porte at the time of the conquest of Foča, Čajniče, Pljevlja and Nevesinje in today's Bosnia and Herzegovina.

[citation needed] In 1420 Ishak Bey organized a successful private campaign in Bosnia to support brother's struggle against his enemies.

Contemporary sources from the senate of Ragusa mention that many Ottoman soldiers were captured, while Ishak Bey escaped with a small group.

[7] In 1439, when he was returning from his trip to Mecca, he was ordered by the sultan to join forces of Şihabeddin Pasha and besiege Novo Brdo, important fortified mining town of Serbian Despotate.