History of The Caliphs, p. 224
Abd al-Malik ibn Marwan was the 5th Umayyad caliph. He was born in Medina, Hejaz. Abd al-Malik was a well-educated man and capable ruler who was able to solve many political problems that impeded his rule. The 14th-century Arab historian and philosopher Ibn Khaldun stated that "`Abd al-Malik ibn Marwan was one of the greatest Arab and Muslim Caliphs. He followed in the footsteps of `Umar ibn al-Khattab, the Commander of the Believers, in regulating state affairs".During his reign, all important records were translated into Arabic, and for the first time, a special currency for the Muslim world was minted, which led to war with the Byzantine Empire under Justinian II. The Byzantines were led by Leontios at the Battle of Sebastopolis in 692 in Asia Minor and were decisively defeated by al-Malik after the defection of a large contingent of Slavs. The Islamic currency was then made the only currency of exchange in the Muslim world. Also, many reforms happened in his time relating to agriculture and commerce. Al-Malik extended and consolidated Muslim rule, made Arabic the state language and organised a regular postal service.
History of The Caliphs, p. 224