pious and respected caliph who attempted to preserve the integrity of the Muslim Umayyad caliphate (661–750) by emphasizing religion and a return to the original principles of the Islamic faith.

His father, ʿAbd al-ʿAzīz, was a governor of Egypt, and through his mother he was a descendant of ʿUmar I (second caliph, 634–644). He received a traditional education in Medina and won fame for his piety and learning. In February or March 706, ʿUmar was appointed governor of the Hejaz. During his tenure of office, he initiated policies that later characterized his reign, particularly his creation of a consultative body of pious men to aid him in his rule.

ʿUmar was elevated to the caliphate by the will of his predecessor, the caliph Sulaymān, in September or October 717. At his accession the stability of the Umayyad caliphate was threatened by the discontent of the Mawālī (non-Arab Muslims) and the “pious opposition,” who resented the Umayyads allegedly for putting political interests ahead of established religious principles. ʿUmar, who was mainly interested in home affairs, attempted no major military conquests, and soon after his accession he lifted his predecessor's disastrous siege of Constantinople (now Istanbul). Initiating a policy of internal consolidation, he dismissed unpopular governors, reformed the taxation system, and granted the Mawālī the same fiscal rights as Arab Muslims.

Although many of his policies seemed untenable, ʿUmar attempted to arrest the disintegration of the Umayyad caliphate by appealing to a broad segment of the Muslim population. He, alone of the Umayyads, was respected by the later ʿAbbāsid dynasty and was highly regarded even among the Shīʿites, schismatic followers of Muhammad's son-in-law ʿAlī.