The fortress is situated in the city of Mosul on the westside of the Tigris river, built on a hill near to the bank of the river. The founder of the for- tress is unknown and the time in which it was built is also unknown. But from the references we have. mention is made that the wall of Mosul is known in the periods fo!llowing In the time of the Umayyad it is said that Marwan B. Muhammad was the one who made it as a city with a diwan and he built a bridge connecting both sides of the city and he also built a wall for the city. In the time of the Abbasid period, the caliph al- Abbas appointed Yahya b. Muhammad instead of Muhammad b. Sul. The new governor looted the city and killed thousands of citizens and pul- led down the wall of the city. It is said also that the city revolted against the caliph al-Rashid, this capliph is said to have pulled down also the wall of the city. 1