Ottoman--The Ottoman Empire located in current day Turkey, Iraq, and into Bulgaria and Romania were able to preserve the classical relics of Europe.
The Ottoman Empire stretched through eastern and southern Europe, northern Africa, and the Middle East to about current day Iraq. They save the classical relics of the Roman, Greek, and Byzantine Empires. This information was protected and with Europeans began regular trading with the Ottoman Empire in the 15th century, the information was reintroduced helping to bring Europe out of the "dark ages".