Their achievements were as diverse as they were impressive. In what was, perhaps, history's first international scientific endeavor, scholars were sent out to gather the texts of the ancient Greeks, Persians, and Hindus, wresting them from oblivion and translating them into Arabic. Thanks to their efforts, the writings of such intellectual fountainheads as Aristotle, Plato, and Hippocrates were saved for future generations.
The great Muslim scholars of eighth-century Baghdad not only saved this knowledge—Christians of the time considered such texts blasphemous and often destroyed them—they studied the material and even improved on it. Building on the ideas of Hippocrates, the Greek father of medicine, they developed detailed studies of anatomy and created four-year medical schools that required doctors to pass a rigorous final exam before they were allowed to practice.
Baghdad's scholars developed a theory of how disease is spread through germs, and they were the first to quarantine patients in hospital wards. They were also advanced in ophthalmology, inventing a surgical technique for removing cataracts from the human eye with the use of a hollow needle—1,000 years before Europeans first employed similar techniques.
Thanks largely to the rigorous empirical research of Ibn al-Haytham, a 10th-century mathematician and astronomer whose optical studies first postulated how the human eye sees, the scientific method became the standard by which all research was conducted. "This spirit of questioning and saying we have to build science on a systematic, consistent basis led to the birth of the new Islamic science," notes George Saliba, a professor of Arabic and Islamic science at Columbia University.
Muslim society's most important contribution to human knowledge came in mathematical disciplines, such as algebra, trigonometry, and logarithms. Muslims also developed the concept of zero and the modern system of numerals still in use today.
Significantly, much of what is known about the Baghdad scholars isn't simply because of their groundbreaking scientific ideas; it's also a result of their society's popularization of a craft they first saw practiced at the farthest edge of their empire: the Chinese art of papermaking. Upon conquering Central Asia in the eighth century, the Muslims seized on the handy substitute for expensive parchment and papyrus and began using the material to record the documents of their expanding bureaucracy.
Indeed, paper was crucial to the creation of the world's first international banking system. An elaborate credit system was created based on the sakk, the Persian word for "check"; the system allowed a merchant to write a check in India and cash it in Spain. Hundreds of thousands of paper documents from the period, discovered in Cairo, reveal the world's first paper economy. "Orders of payment, the equivalent of modern checks, were drawn in amounts upwards from one dinar," write Jonathan Bloom and Sheila Blair in their book Islam: A Thousand Years of Faith and Power. "Letters of credit drawn upon well-known merchants or bankers enabled traders traveling far from their homes to avoid transporting large sums and quantities in gold."
The Baghdad scholars found the new paper medium equally useful for transcribing ancient texts and sharing scientific writings and other intellectual material. "What followed was an explosion of books," says Bloom, whose own book, Paper Before Print: The History and Impact of Paper in the Islamic World, recounts the impact of everything from science and religious texts to cookbooks and folk tales like the Tales From a Thousand and One Nights.
"It was as revolutionary as the printing press," says Bloom. "It essentially democratized knowledge and helped connect this huge society spread across three continents."