The second wave of Arab expansion under the Umayyads (662–750)
• After a bloody struggle with the Shiites, the Sunnite family of the Umayyads eventually gained the upper hand and assumed the Caliphate.
• The capital of the Umayyad Caliphs became Damascus, and Syria became the centre of Islamic power.
• The first Umayyad Caliph (13 in all) united the Arab tribes and established a centralized, bureaucratic state, with a regular army, chancery, postal system, and intelligence service. Arabic was made the official language. Civil society became Islamized.
• The office of the Caliph became hereditary (dynastic principle).
• The Umayyad Empire stretched from Spain to the Himalaya.