Under the Sasanians, Syriac became an important language of the administration and intellectuals, rivaling Greek. Several cities developed centers of higher learning in the Sasanian Empire, including Mosul, al-Hira, and Harran (famous for the Pythagorean School of the Sabeans). The Grand School was the main center of learning in the Persian capital Ctesiphon, but little is known about it. Perhaps the most famous center of learning in Persia was the Academy of Gundishapur, teaching medicine, mathematics, astronomy, and logic. The academy was later instrumental in founding the Muslim city of Baghdad as a center of learning, and serving as the model for the first Muslim hospital ("bimaristan") at Damascus.