Excerpts from Books and Wikipedia
"The Abbasid general Abdullah ibn-Ali invited eighty members of the Umayyad family to a banquet at abu-Futrus near Jaffa on June 25, 750, and during the course of the feast had them all slaughtered. . . . Non-Arabs believed the caliphate had been founded to spread the word of Islam, not to advance Arab interests. . . . The accession of the Abbasids marked a decisive shift of power in the Islamic world away from Arabs in favor of new converts who were now free to advance in government. It also marked the end of the political unity of the Muslim world. Only one significant member of the Umayyad family survived. Abd ar-Rahman escaped to Spain, where he founded a breakaway state." [1001 Days]