Probably the most exquisite mosque of western Islamic land, founded by ‘Abd al-Rahman I in 786, enlarged several times, 832-48 under Abd al-Rahman II, 962 under al-Hakam II, and 987 by al-Mansur, the vizir of Hisham II (this time it was extended to the west). The Mosque has an intricate hypostyle arrangement with double-tiered, arched supports, ribbed domes above the maqsura, and a unique mihrab-chamber with mosaic decoration.