Muawiyah I (602 – April 29 or May 1, 680) is the first Caliph of the Umayyad Dynasty.

After the conquest of Mecca by the Muslims, Muawiyah's family converts to Islam.

Muawiyah and the Islamic prophet Muhammad are brothers-in-law after Muhammad marries his sister, Ramla bint Abi Sufyan.

Muawiyah become sa scribe for Muhammad, and during the first and second caliphates of Abu Bakr and Umar (Umar ibn al-Khattab), fights with the Muslims against the Byzantines in Syria.

When his elder brother Yazid ibn Abi Sufyan (Governor of Syria) dies of the plague, Umar then appoints Muawiyah as Governor of Syria in 640 CE.

However, when Ali is appointed the fourth and final Rashidun Caliph, he expels Muawiyah from the Governorship.

Muawiyah refuses to obey Ali, and has some level of support from the Syrians in his rebelliousness, among whom he is a popular leader.

Ali calls for military action against Muawiyah, but the reaction of the political classes in Medina is not encouraging, and thus Ali defers.

Eventually, Ali marches on Damascus and fights Muawiyah's supporters at the inconclusive Battle of Siffin (657 CE).

Ali's son Hasan ibn Ali signs a truce and retires to private life in Medina.

Muawiyah thus establishes the Umayyad Caliphate, which is to be a hereditary dynasty, and governs from Damascus in Syria instead of Medina in Arabia.

As caliph, Muawiyah develops a navy in the Levant and uses it to wage a war against the Byzantine Empire in the Aegean Sea and the Sea of Marmara.

The Caliphate conquers several territories, including Cyzicus, which are subsequently used as naval bases.

The war ends in an unsuccessful siege of Constantinople.

Muawiyah I is a reviled figure in Shia Islam for several reasons.

Firstly, because of his involvement in the Battle of Siffin against Ali, whom the Shia Muslims believe was Muhammad's true successor); secondly, for the breaking of the treaty he made with Hasan ibn Ali, after the death of Hasan ibn Ali, one of broken terms being appointing his son Yazid as his successor; thirdly, on account of his responsibility for the killing of Hasan ibn Ali by bribing his wife Ja'dah binte Ash'as to poison him; and fourthly for trying to distort Islam to suit his rule, and fifthly, for the deaths of various Companions of Muhammad.