Freely (Storm on Horseback: The Seljuk Warriors of Turkey, 2008, etc.) profiles the various caliphates that fostered scholarship and scientific inquiry during Europe’s Dark Ages.
As the eighth century drew to a close, the author writes, Baghdad became a beacon illuminating classical antiquity. The Abbasid caliphate, which had held sway there for several centuries, reached its peaking during the reign of Harun al-Rashid (786–809), when Baghdad’s scholars plumbed the known world for long lost books and documents, including many from the ancient library at Alexandria. In Baghdad’s library, known as the House of Wisdom, Greek texts were painstakingly translated into Arabic. But Islamic scholars did more than just translate, the author notes; they critiqued Greek thinkers from Archimedes and Aristotle to Zeno. They questioned ideas on the nature of reality, corrected astronomical observations and probed medical tracts and mathematical theorems. In once instance, three wards of a Baghdad caliph marched a measured distance from north to south in the desert until the elevation of Polaris had changed by exactly a single degree; multiplying by 360, they arrived at a circumference of the earth only 92 miles short of what today’s science confirms. In time, Cairo and Damascus succeeded Baghdad as centers of Islamic study, flourishing from the tenth into the 14th centuries under the Fatimids and other dynasties. Umayyad caliphs ruled the region of southern Spain known to Arabs as Al-Andalus, which offered another tolerant, enlightened bastion for scholars. As Christians came there to study, Greek texts that had once flowed into Arabic were poured into Latin, and the early flame of the European Renaissance flickered. Freely extensively documents Islamic works that gave us words like algebra and algorithm and dusted off the even more ancient Hindu numerals now universally employed.
A chewy study of the preservation and transportation of classical Greek thought. See Jonathan Lyons’ The House of Wisdom (2009) for a more accessible account of the Arab influence on Western civilization.