 Most notable was the development of Arabic prose and poetry, termed by "The Cambridge History of Islam" as its "golden age".Commerce and industry (considered a Muslim Agricultural Revolution) and the arts and sciences (considered a Muslim Scientific Revolution) also prospered under Abbasid caliphs al-Mansur (ruled 754–775), Harun al-Rashid (ruled 786–809), al-Ma'mun (ruled 809–813) and their immediate successors.The capital was moved from Damascus to Baghdad, due to the importance placed by the Abbasids upon eastern affairs in Persia and Transoxania.