Islam / Caliph /
Other spelling: Ummawiyy, Ummayyad
The Umayyads were located most of the time to Damascus in Syria.
The were the descendants of Umayya ibn Abdi sh-Shams, a member of the Quraysh family of Mecca.
The first Umayyad Caliph was Mu'awiyya, who fought against Caliph Ali until Ali was murdered in 661.
There are two Umayyad families, from 661 to 684 it was the Sufaynid branch, but from 684 the Marwanid branch took over the control.
Even though the Caliphate was a religious institution, the Umayyads were to a large extent secular rulers, who participated only partly in religious administration and questions. Historical sources present the Umayyad Caliphs as tyrannical so often that you get the impression they were not Muslims at all. This is particularly the case with historical sources written by Shi'is, while Sunni writers have an ambiguous relationship to them. Only Umar 2 (717-20) and Yazid 3 are generally considered to have been just and fair.
The Umayyads are most famous for the buildings they erected, like the Dome of the Rock and the Al-Aqsa Mosque in Jerusalem (690s) and the Umayyad Mosque in Damascus (705).
The Umayyads extended its territories massively during its Caliphate, at least until the 710s. Most of the new land was to the west in Africa and the Iberian peninsula, but they also reached the borders of China and northern India. There were a number of unsuccessful attempts to conquer Constantinople, in 674-78 and 717-18.
The time of the Umayyads was not a time of conversion to Islam, as people converting to Islam, were exempted from certain taxes, like the jizya, the tax of the dhimmis.
The Umayyads were overthrown in 750 by the Abbasids. The Abbasids had begun a revolt in Khurasan in Persia, following tensions and dissatisfaction over difference in treatment between Muslims of true Arab origin, and non-Arab converts to Islam in the Arab army. The Abbasids addressed this, and met a weak enemy that had relied too much upon forces that were all too happy to see the Umayyads gone.
But even with the Umayyads out of Damascus, they were not all cut away from power, as some members of the family moved to Muslim Spain, where their leader seized the position as emir. From 756 to 1031 the Umayyads ruled Spain, and for the last 100 years of this period the emir also called himself Caliph.