Wikipedia: History of Islam

Muhammad was born presumably between 570-580 A.D. Both of his parents died at very early ages and he was raised by his uncle Abu Talib. He married a wealthy widow, Khadija, and followed his career as a trader. Between the ages of 30 and 40, he experienced his initial prophetic call, when he was alone in the hills above Mecca? for meditation. He reported that he had been chosen, like the prophets before him, as the agency of a sacred message. Being ignored and rejected at the beginning, he began to gain followers mainly from lower classes. The first wealthy men accepting his prophethood were Abu Bakr and Umar. He was severely opposed by the residents of Mecca for attacking the pagan gods of Arabic peninsula. As his opponents in Mecca (one of his uncles, Abu Lahab, was among his worst enemies) began to organize to give an end to his prophecy, he withdrew with many of his followers to Medina? in September of A.D. 622. This migration is called the Hegira (or Hijra), and its year is used to establish the Muslim year-count scheme or era; 622 is the year 1 A.H. (Annus Hegirae). The A.H. system dates from the beginning of the lunar year in which the Hegira took place, so that it does not neatly coincide with the Julian or Gregorian year numbers. After three major battles and one last battle with Mecca, almost all Arabia fell to Muhammad in 630 and great number of tribes established alliance with the Prophet.

After Muhammad's death on June 8, 632, Abu Bakr was accepted as head of the Islamic state. The next three caliphs were all relatives of the prophet, but were succeeded by another household of the same Meccan tribe, a change not universally accepted, leading to the major division in Islam between the majority of Sunnites and the minority of Shiites. The new household was the first major caliphate dynasty, the Umayyads, who conquered the [Sassanian empire]? (Persia) and the southern Byzantine provinces as far as Spain. See also Ali Ben Abu Talib

The majority of this new empire was of course non-Islamic, and aside from a protection tax (jiszya) the conquered people found their religions tolerated. Nonetheless the new religion penetrated deeply, to the point where conversions had to be discouraged since they were undermining the tax system. At the same time the Umayyads had dedidicated their prestige to conquering the [Byzantine empire]?, and started running into real opposition from the Orthodox provinces. Thus there was a revolution in 750 and a new dynasty, the Abbasids, took the caliphate, marking the transition to a more settled empire.

The political unity of Islam began to disintegrate almost immediately. The emirates, still recognizing the theoretical leadership of the caliphs, drifted into independence, and a brief revival of control was ended with the establishment of two rival caliphates: the Fatimids? in north Africa, and the Umayyads in Spain (the emirs there being descended from an escaped member of that family). Eventually the Abbasids ruled as puppets for the Buhyahid? emirs.

Around this time a series of new invasions swept over the Islamic world. First the newly converted Seljuk Turks swept across and conquered most of Islamic Asia, hoping to restore orthodox rule and defeat the Fatimids but soon falling prey to political decentralization themselves. After the disastrous defeat of the Byzantines at the [Battle of Manzikert]? (1071) the west launched a series of Crusades and for a time captured Jerusalem. Saladin however restored unity, defeated the Fatimids and recaptured the city, and later crusades accomplished little save the sack of Constantinople, leaving the Byzantine empire open to conquest.

Meanwhile, though, a second and far more serious invasion had arrived: that of the Mongols, who conquered most territories up to the borders of Egypt, and permanently ended the Abbasid caliphate. Their wanton destruction left the Islamic world damaged and confused. However it reached a new peak under the Ottoman empire, a tiny state in Turkey that conquered the Byzantines and extended its influence over much of the Muslim peoples.

In the 18th century there were three great Muslim empires: the Ottoman in Turkey, the Middle East, and the Mediterranean; the Safavid? in Iran; and the Mogul in India. By the end of the 19th century, all three had been destroyed or weakened by massive influence of Western civilizations. In the 20th century this trend has been reversed and almost no Muslim country under political domination of outside powers has been left. This new vitality of Muslims have been accompanied by a religious awakening and cultural renaissance.

Muhammad ibn Abd al Wahhab (1703-29) led a religious movement in the east of Arabia that saw itself as purifying Islam. His most important follower was the then leader of the family of ibn Saud.