During late antiquity, in the Byzantine empire many Greek classical texts were preserved. Many Syriac translations were done by groups such as the Nestorians and Monophysites.[60] They played a role when they translated Greek classical texts into Arabic under the Caliphate, during which many types of classical learning were preserved and in some cases improved upon.[60][lower-alpha 1] In addition, the neighboring Sassanid Empire established the medical Academy of Gondeshapur where Greek, Syriac and Persian physicians established the most important medical center of the ancient world during the 6th and 7th centuries.[61]