Arabian dynasty of the Islamic Empire who reigned as caliphs (civic and religious leaders of Islam) from 661 to 750, when they were overthrown by Abbasids. A member of the family, Abd al-Rahmam, escaped to Spain and in 756 assumed the title of Emir of Córdoba. His dynasty, which took the title of caliph in 929, ruled in Córdoba until the early 11th century.