His mother was Theodora Kantakouzene, the daughter of Byzantine emperor John VI Kantakouzenos and Irene Asanina.
[1] He also called Ilyas Bey, the ruler of Saruhan (a small Turkmen beylik in west Anatolia formed after the disintegration of the Sultanate of Rum), for a joint operation against Phocaea.
After the failure of the 1358 operations, Orhan came to Scutari (modern Üsküdar) on the Asiatic shore of the Bosporus for talks and agreed to pay 30,000 ducats as a ransom.
As a part of the agreement, Halil was engaged to his first cousin, Irene Palaiologina, the 10-year-old daughter of John V Palaiologos.
Since Halil's elder brother Süleyman Pasha had already died, the Palaiologos family hoped to see him as the new ruler of the Ottoman beylik.