This empire's decline was completed after it was defeated in the Battle of Zab, though Abd ar-Rahman managed to start another incarnation of it in Cordoba, Spain.  
This empire's decline was completed after it was defeated in the Battle of Zab, though Abd ar-Rahman managed to start another incarnation of it in Cordoba, Spain.  It featured an internal clash between the Sufyanids and the Marwanids, which was mostly ended by the rule of Abd al-Malik following the deaths of Yazid I and Mu'awiyah II.  At its greatest extent in the early 8th century, this empire based in Damascus ruled over an area extending from Spain nearly to India.  For 10 points, name this first of the Muslim Empires, which was later replaced by the Abbasids.
This empire's decline was completed after it was defeated in the Battle of Zab, though Abd ar-Rahman managed to start another incarnation of it in Cordoba, Spain.  
{Umayyad} Caliphate or Empire