Jalal ad-Din was an old man in AD 769, with white whiskers, when the Caliph Abd ar-Rahman asked him to lead a delegation of Muslims from Constantinople to a heathen Bulgar Khan named Telerikh. The purpose was to attempt to convert him and his people to Islam. Accompanying him was Da'ud ibn Zubayr, a military officer, and Malik ibn Anas and Salman al-Tabari, the two both guards and aids. After much proselytizing and debate, the Khan converted to the Muslim faith because of the nature of the Christian heaven and because the Caliphate commanded a stronger empire than the Pope.