Mus Castle The Mus Castle is in the center of the city of Mus. It was built following the Mongols invasion, and occupied by Muslim forces under Caliph Osman for many years. During this period, it housed frequent battles between these armies as well as with Armenian overlords appointed to administer territory near Baghdad on behalf of Abbasid Caliphs. Mus Castle was completed in 27 Hijra (about 677 AD) The castle fell into the hands of Muslims during the Omar period: As a result, it was essentially given over to Muslim control. Powerful wars led to considerable destruction with historic monuments in this area. The Arab Cemetery (destroyed), Seljuk Cemetery and Ottoman Cemetery on the west side of the castle now lie spread out among one another as a park administered by the municipality. It is now used by many locals for picnicking purposes.