Marwan I, Umayyad general and caliph (d. 685)
Marwan ibn al-Hakam ibn Abi al-As ibn Umayya (Arabic: مروان بن الحكم بن أبي العاص بن أمية, romanized: Marwān ibn al-Ḥakam ibn Abī al-ʿĀs ibn Umayya), commonly known as Marwan I (623 or 626 – April/May 685), was the fourth Umayyad caliph, ruling for less than a year in 684–685. He founded the Marwanid ruling house of the Umayyad dynasty, which replaced the Sufyanid house after its collapse in the Second Muslim Civil War and remained in power until 750.

During the reign of his cousin Uthman (r. 644–656), Marwan took part in a military campaign against the Byzantines of the Exarchate of Africa (in central North Africa), where he acquired significant war spoils. He also served as Uthman's governor in Fars (southwestern Iran) before becoming the caliph's katib (secretary or scribe). He was wounded fighting the rebel siege of Uthman's house, in which the caliph was slain. In the ensuing civil war between Ali (r. 656–661) and the largely Qurayshite partisans of A'isha, Marwan sided with the latter at the Battle of the Camel. Marwan later served as governor of Medina under his distant kinsman Caliph Mu'awiya I (r. 661–680), founder of the Umayyad Caliphate. During the reign of Mu'awiya's son and successor Yazid I (r. 680–683), Marwan organized the defense of the Umayyad realm in the Hejaz (western Arabia) against the local opposition. After Yazid died in November 683, the Mecca-based rebel Abd Allah ibn al-Zubayr declared himself caliph and expelled Marwan, who took refuge in Syria, the center of Umayyad rule. With the death of the last Sufyanid caliph Mu'awiya II in 684, Marwan, encouraged by the ex-governor of Iraq Ubayd Allah ibn Ziyad, volunteered his candidacy for the caliphate during a summit of pro-Umayyad tribes in Jabiya. The tribal nobility, led by Ibn Bahdal of the Banu Kalb, elected Marwan and together they defeated the pro-Zubayrid Qays tribes at the Battle of Marj Rahit in August of that year.

In the months that followed, Marwan reasserted Umayyad rule over Egypt, Palestine, and northern Syria, whose governors had defected to Ibn al-Zubayr's cause, while keeping the Qays in check in the Jazira (Upper Mesopotamia). He dispatched an expedition led by Ibn Ziyad to reconquer Zubayrid Iraq, but died while it was underway in the spring of 685. Before his death, Marwan firmly established his sons in positions of power: Abd al-Malik was designated his successor, Abd al-Aziz was made governor of Egypt, and Muhammad oversaw military command in Upper Mesopotamia. Although Marwan was stigmatized as an outlaw and a father of tyrants in later anti-Umayyad tradition, the historian Clifford E. Bosworth asserts that the caliph was a shrewd, capable, and decisive military leader and statesman who laid the foundations of continued Umayyad rule for a further sixty-five years.