While the Muslims administered the city, the population of Damascus remained mostly Christian—Eastern Orthodox and Monophysite—with a growing community of Muslims from Mecca, Medina, and the Syrian Desert. The governor assigned to the city which had been chosen as the capital of Islamic Syria was Mu'awiya I. After the death of Caliph Ali in 661, Mu'awiya was chosen as the caliph of the expanding Islamic empire. Because of the vast amounts of assets his clan, the Umayyads, owned in the city and because of its traditional economic and social links with the Hijaz as well as the Christian Arab tribes of the region, Mu'awiya established Damascus as the capital of the entire Caliphate. With the ascension of Caliph Abd al-Malik in 685, an Islamic coinage system was introduced and all of the surplus revenue of the Caliphate's provinces were forwarded to the treasury of Damascus. Arabic was also established as the official language, giving the Muslim minority of the city an advantage over the Aramaic-speaking Christians in administrative affairs. It is critical to note that, at the time Damascus was conquered by the Muslims, the majority of Arabs were either pagans or Christians. Damascus itself was predominantly Aramaic with Arab speaking people.