 Sassanid Emperor Khosrau I held it to ransom after Byzantine Emperor Justinian I had failed to defend it.The Abbasid caliph Harun al-Rashid restored Manbij at the end of the 8th century, making it the capital of the frontier province of al-Awasim.Afterward, the city became a point of contention between the Byzantines, Arabs and Turkic groups.