The Mosque of ‘Umar. From the Bradt Guide: It was named after Caliph ‘Umar, second caliph after Abu Bakr who succeeded the Prophet Mohammed. ‘Umar conquered Syria in 636 and this is thought to be one of the oldest surviving mosques anywhere, though the current building is heavily reconstructed and dates from the 12-13th century under the Ayyubids. It is built on the site of an earlier temple. Its courtyard if now roofed and has double arcades on the west and east sides, but would originally have housed a marketplace and sleeping areas, illustrating how closely early Islam was linked with commerce.