Muslim civilization had grown dramatically since the founding of the religion in Mecca in about 610 and Mohammed’s emigration to Medina in 622. The territorial and cultural expansion eastward and westward during the period of the Umayyad caliphs in the eighth century created an empire that extended from the borders of China to the Atlantic Ocean, from the Sahara to the Caspian Sea, from India to al-Andalus. With the rise to power of the Abbasid caliphs in the middle of the eighth century, the capital of the Islamic empire moved east, from Damascus to Baghdad. A dramatic rise in interest in Hellenistic and Persian culture followed, and the writing of local, Arab-nationalist literature that had characterized the Umayyad period was replaced by a universal literature. Much of it was scientific. As well as mathematics and cosmography, it reflected a vivid interest in the history and geography of the many peoples with whom the expansion of the seventh and eighth centuries had brought the Arabs into contact.
