Öz Beg continued the alliance with the Mamluks begun by Berke and his predecessors. He kept a friendly relationship with the Mamluk Sultan and his shadow Caliph in Cairo. In 1320, the Jochid princess Tulunbay was married to Al-Nasir Muhammad, Sultan of Egypt. Al-Nasir Muhammad came to believe that Tulunbay was not a real Chingissid princess but an impostor. In 1327/1328, he divorced her, and she then married one of al-Nasir Muhammad's commanders. When Öz Beg learned of the divorce in 1334/1335, he sent an angry missive. Al-Nasir Muhammad claimed that she had died and showed his ambassadors a fake legal document as proof, although Tulunbay still lived and would only pass away in 1340.