"Between Muhammad’s death and the collapse of the Umayyad caliphate in 750, Arab armies appeared everywhere from central Asia, through the Middle East and north Africa, throughout the Visigothic Iberian Peninsula, and even into southern France. They imposed Islamic governments and introduced new ways of living, trading, learning, thinking, building, and praying. The capital of the vast caliphate they established would be Damascus itself, crowned with its Great Mosque—one of the masterpieces of medieval architecture anywhere in the world."