Early reforms under Islam

Many social changes took place under Islam between 610 and 661, including the period of Muhammad's mission and the rule of his four immediate successors who established the Rashidun Caliphate.

Historians generally agree that changes in areas such as social security, family structure, slavery and the rights of women improved on what was present in existing Arab society. For example, according to Lewis, Islam "from the first denounced privilege, rejected hierarchy, and adopted a formula of the career open to the talents."

Bernard Lewis believes that the advent of Islam was a revolution which only partially succeeded due to tensions between the new religion and very old societies that the Muslims conquered. He thinks that one such area of tension was a consequence of what he sees as the egalitarian nature of Islamic doctrine. Islam from the first denounced aristocratic privilege, rejected hierarchy, and adopted a formula of the career open to the talents. Lewis however notes that the equality in Islam was restricted to free adult male Muslims, but even that "represented a very considerable advance on the practice of both the Greco-Roman and the ancient Iranian world."

Bernard Lewis writes about the significance of Muhammad's achievements:

The Constitution of Medina, also known as the Charter of Medina, was drafted by Muhammad in 622. It constituted a formal agreement between Muhammad and all of the significant tribes and families of Yathrib (later known as Medina), including Muslims, Jews, and pagans. The document was drawn up with the explicit concern of bringing to an end the bitter intertribal fighting between the clans of the Aws (Banu Aus) and Banu Khazraj within Medina. To this effect it instituted a number of rights and responsibilities for the Muslim, Jewish, and pagan communities of Medina bringing them within the fold of one community-the Ummah.

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