The founder of the Umayyad dynasty, caliph from 661-680.
Muawiya was the son of Abu Sufyan, the leader of the Abd Shams clan. Most of the members of Abd Shams had rejected Muhammad's prophetic mission until Muhammad's conquest of Mecca in 630. Muawiya and his father are considered to be among those enemies who were reconciled to Islam through gifts. Muawiya then served as one of Muhammad's scribes.
During the reign of Abu Bakr, Muawiya served in the armies sent against the Byzantines in Syria. The caliph Umar appointed him governor of Damascus; his kinsman Uthman subsequently enlarged his governorship to include what is today Syria and north-western Iraq. Muawiya consolidated his power over the region by building up a strong army which he used effectively to launch both land and sea attacks against the Byzantines.
The murder of Uthman at the hands of discontented Egyptians and the accession of Ali to the caliphate in 656 gave Muawiya the opportunity to expand his power. Ali had his own difficulties establishing his legitimacy, and by the time he requested Muawiya to give him the oath of allegience, the Syrian population was generally of the opinion that Ali was responsible for Uthman's murder; thus, Muawiya refused to pay him allegience. The two men confronted each other with their armies at Siffin in early 657, where Muawiya called for an arbitration. The arbitration solved nothing, but it did serve to delegitimize Ali in the eyes of some of his supporters. The Syrians acknowledged Muawiya as caliph, and he was able to take control of Egypt later that year. Thus with Ali's assassination in 661, Muawiya easily moved into Iraq and asserted his claim to the caliphate. Ali's eldest son, Hasan, who briefly succeeded his father, was persuaded to abdicate.
With Muawiya's accession, the seat of the caliphate was moved to Damascus. Muawiya continued raids against the Byzantines, both in Anatolia and North Africa. The conquest of Tripolitania and Ifriqiyah led to the founding of the garrison city Kairouan in 670 as a base for continuing forays into what is today Algeria. Naval expeditions against the Byzantines and raids into Anatolia led to a three-year seige of Constantinople (674-677). In the east, the borders of the Muslim empire were expanded to Khorasan and the Oxus River.
Internally, Muawiya governed through a combination of Arab tribal tradition and Byzantine administrative structures. The conquests of the "Four Righteous Caliphs" had led to an immigration of Arab tribes into Iraq and Syria, each with competing interests. Having secured the loyalty of the Syrian tribes, Muawiya conciliated the Iraqi tribes by adopting the traditional council of notables in which each tribe is represented by its leader. These councils were linked to the caliph through his governors, who were generally his kinsmen. However, this arrangement was not sufficient in itself to administer a growing empire. To solve this problem, Muawiya made use of Byzantine administrative structures, the key positions of which were held by Christians who in some cases came from families that had served the Byzantine government. Muawiya is credited with the creation of specialized bureaus, known as diwans, to increase the centralization of the government; two such diwans created to improve communications are the diwan al-khatam, the chancellery, and the diwan al-barid, the postal service.
Muawiya's most lasting innovation was his designation of his son Yazid as his successor; this move established hereditary succession as the norm for the caliphate. Although he secured allegience to Yazid before his death, resistence to his innovation manifested itself upon Yazid's accession. Later generations of Muslims held conflicting views about his reign: to some, he was a clever and successful ruler, while to others, he usurped the caliphate and deviated from the practice of Muhammad and the "Four Righteous Caliphs".