Under the rule of the Umayyad caliphs, the then young Muslim world reached its maximum expansion and the greatest levels of culture and creativity. However, it was a highly unstable empire, in which the caliph's power was continuously questioned by rebel factions. During about one hundred years, from 644 to 759, up to fifteen caliphs reigned, of which six were eventually murdered. There were three great civil wars and more than ten generalised revolts.
The family descended from Umayyad, who shared a great-great-grandfather with Muhammad, from the Hashemite family. As both families belonged to the same tribe -the Quraysh-, and close to power, they hated each other. In fact, the Umayyad were the main opposers to the new Muslim religion, until they were subdued by Muhammad and converted in 630.
The first Umayyad caliph was Uthman, elected in 644 by a community of tribal leaders (shura) according to the Quraysh tradition, as he was one of the first to be converted to Islam, with the opposition of his entire family. Nevertheless, when caliph, he started creating a dynasty, prioritizing Umayyad members to become governors. His prosperous and politically liberal reign gave place to the first intrigues, caused by tribal fights, personal enemies of the caliph and foreign powers afraid of the Islamic expansion -Uthman multiplied by three the Empire's territory-. But it was especially Ali, another disciple of the prophet, who denied the validity of shura decisions and defended Muhammad had personally designed him as successor before his death. A revolt appeared in Egypt eventually finished with the caliph's assassination in 656.
Sunnites, shiites and kharijites
Officially, Ali was proclaimed caliph by the families from Medina. However, Muawiyah, governor of Siria and Uthman's cousin, accused Ali of inspiring the murder and doing nothing to convict the murderers. After supporting, but not participating, in the rising led by Aisha, Muhammad's widow, which eventually failed, he organised his powerful Syrian army and confronted Ali in Siffin. The battle was a draw, and Ali finally bargained with Muawiyah a truce -Adroj arbitration (658)-, by which both kept their former positions. This caused a faction of Ali's followers, belonging to Hanifa and Tamin tribes, consider him a traitor and separate, named kharijites and under the motto "there is not rule but God's", defendind the caliph cannot decide the partition of power in the World. Ali could not crush all the rebels during the mutiny, and they eventually killed him three years later.
Muawiyah, already self-proclaimed caliph in 660, hurried to the capital, Kufa, with his reorganised army from Damascus, to get the throne. Ali's first-born son, Hasan, not counting with enough forces, fled to Medina and left free space to Muawiyah. His brother Husayn tried to get his rights back, but was defeated and killed in Karbala in 680. At his death in the beginning of that same year, the caliph Muawiyah had officially created the Umayyad dynasty, when forcing the noblemen to accept his son Yazid as his successor. This allowed him to consolidate caliphal power, but he also gained many enemies that continuously fought for the throne.
From this moment on, authority was always divided in the Islamic World. Opposing Muslim orthodoxy, or sunnism, the defeated followers of Husayn constituted the Shiite sect, that would be back to war several times, specially in Arabia and Irak, and was eventually a key element in the fall of the dynasty. Basically, shiites did not accept Umayyad authority, and created the Imam title instead, as spiritual leader -in order to differentiate it from the more terrenal caliph title- for Ali's heir. Centuries later, an imam died without any descendants, which made the Shiism break into several rival sub-sects.
Meanwhile, kharijites were a faction self-declared as the defender of Islamic purity. This sect, now practically disappeared, argued the caliph should not be designated in an hereditary way, but it should arise from the community. After killing Ali, they constituted an important opposition focus against the Umayyad, causing several local revolts specially among berbers of recently conquered Maghreb, in Mesopotamia, Irak and North Arabia, although Shiism became a larger problem.
Caliph at the caliph's place
Yazid died in 683 while besieging Mecca, trying to defeat Abdallah ibn Zubayr, who had supported Husayn and, at his death, proclaimed himself caliph in Arabia and Egypt. Abdallah caused great headaches to Damascus caliphs, as he had the main Islamic pilgrimage place under control. In order to compete with it, the Umayyad built the Mosque of the Rock in Jerusalem. The existence of two caliphs lasted for ten years, as one of the main Syrian tribes, the Qaysites, supported him against the Kalbites, allied to Damascus. The fight between these tribes was a long civil war, which a third faction joined, that of rebel al-Mukhtar, strong in Irak and defending the rights of another Ali's heir -Muhammad ibn al-Hanafiyya- without his permission.
The new Damascus caliph, al-Malik, chose to wait until both rebel factions destroyed each other, instead of attacking openly. Eventually, al-Mukhtar was defeated in Kufa by Abdallah in 687. That was the momento to attack his weakened army, that fell in Mecca five years later, after a harsh siege which destroyed the Holy Place of the Kaaba. Abdallah was beheaded, and his body exposed for potential rebels. The new sovereign of the whole Islamic world had a reign of centralization and internal peace. Thanks to the governor of Irak and personal lieutenant, al-Hajjaj ibn Yusuf, no revolt was succesful during those years. This allowed carrying on the conquests and reaching the maximum extension of the Empire, from Spain to India.
When great al-Malik's sons, less authoritary, reigned, rebels stroke back. When inheriting such a large and heterogeneous Empire, in which Arabs enjoyed privileges and tax exemptions over non-Arabs, union was progressively more difficult to keep. Although one of the sovereigns, Umar, tried to abolish this differentiation, the consequent tax income drop became impossible, and going back to tax raising led to general revolts, specially in Transoxiana in 734. To make things worse, the caliph Hisham was defeated all along the Empire borders (Tours, Samarkand, Akroinon, etc.) and more unhappiness caused new rebellions in a territory impossible to control: Zayd's shiites in Irak, Berbers in North Africa -Morocco and Spain were lost in 740-, kharijites in Iran, and the feuds of conflictive Syrian tribes bleeding each other. Meanwhile, decadence and palace intrigues were increasing: the family members, togethers with generals and governors, were fighting each other for the power -the drunkard, corrupt al-Walid II was murdered by his own cousin Yazid, who proved no more brilliant-.
The Abbasid executioners
The end of the Umayyad came from the hand of the Abbasids, descendants of Abbas and -far- political family of Muhammad. It is in fact believed that they were not Arabs, but converse Persians, which explains why they had the support of non-Arab citizens from Iran. Using the excuse that the Umayyad had betrayed the Islam spirit, they attracted shiites and kharijites, gathering all possible opposition -needless to say that, after the dynasty overthrown, they kept opposing the new caliphs-.
The Abbasids consolidated their power in Khurasan, North-eastern Iran, far from central power, and started an open revolt in 747. In 749, the Abbasid Abu proclaimed himself caliph in Kufa. Next year, they defeated the Umayyad in Zab, and the caliph Marwan II was persecuted and killed in Egypt. Liberating all the resentment of a century, the winners outraged the tombs of the Umayyad and killed the remaining members of the family. Only one saved, Abd al-Rahman, who fled to the border province of Cordoba, and there extended the dynasty, but that is a different story.