The greeks made many important contributions to western civilization. of the four items listed below, which is the most important greek contribution

The Umayyads ruled the first empire after the death of Muhammad. They made their capital in the city of damascus and expanded Muslim power into Spain. In 750, they were replaced by the abbasids , who ruled from baqhdad . This marked the beginning of Islam's Golden age.

Explanation: In short I think it was the Umayyads sorry if wrong

Hope this was a little helpful