Umayyad Caliphate

The Umayyad Caliphate was the second of the four major Islamic caliphates established after the death of Muhammad.
It was the largest empire in the world at the time. It is the fifth largest empire in history.
It was ruled by the Umayyad Dynasty (, "Banu Umayyah") who came from Mecca, in present-day Saudi Arabia. Damascus was the capital from 661–744, Harrran from 744–750, and in exile their capital was Córdoba (756–1031).
Origins.
According to tradition, the Umayyad family (also known as the Banu Abd-Shams) and the Islamic Prophet Muhammad both have a common ancestor, Abd Manaf ibn Qusai. Muhammad descended from Abd Munaf via his son Hashim, the Umayyads descended from Abd Munaf via a different son, Abd-Shams. The two families are therefore considered to be different clans (those of Hashim and of Umayya, respectively) of the same Arabian tribe (that of the Quraish).
The Umayyads and the Hashimites were bitter rivals. The rivalry came from the initial opposition of Abu Sufyan ibn Harb, the grandson of Umayya, to Muhammad and to Islam. He tried to get rid of the new religion by waging a series of battles. But eventually he accepted Islam, as did his son (the future caliph Muawiyah I), and the two provided much-needed political and diplomatic skills for the management of the quickly expanding Islamic empire.
The origins of Umayyad rule date back to the assassination of Uthman in 656. At this time Ali, a member of the Hashim clan and a cousin of Prophet Muhammad, became the caliph. He soon met with resistance from several factions, and moved his capital from Medina to Kufa. The resulting conflict, which lasted from 656 until 661, is known as the First Fitna ("time of trial").
Ali was first opposed by an alliance led by Aisha, the widow of Muhammad, and Talhah and Al-Zubayr, two of the Companions of the Prophet. The two sides clashed at the Battle of the Camel in 656, where Ali won a decisive victory.
When Ali was assassinated in 661, Muawiyah marched to Kufa. There he persuaded a number of Ali's supporters to accept him as caliph instead of Ali's son, Hasan. Then he moved the capital of the caliphate to Damascus. Syria would remain the base of Umayyad power until the end of the dynasty.