Tayādhūq, also known as Theodocus/Théodoros (d. early 8th century AD), was educated in the Gondēs̲h̲āpūr School and served the Sassanid kings. During this period, he contacted the Umayyad court and became the physician of Hajjāj ibn Yūsuf (d. 715 AD), the general governor of the Eastern regions of the caliphate. In addition to his knowledge on the Sassanid scientific tradition, Tayādhūq had a significant role in transferring this tradition to the Islamic world. His ideas were later followed by polymath physicians such as Rhazes (Abū Bakr al-Rāzī, d. 925 AD), Avicenna (Ibn Sīnā, d. 1037 AD), and others who lived after him. His medical works were of great importance to the development of early Islamic medicine. Therefore, this study will attempt to illuminate this forgotten scholar's medical knowledge, the works he produced, and finally illustrate his influences on later Muslim physicians.
Keywords: Avicenna; Gondēs̲h̲āpūr; Islamic medicine; Rhazes; Sassanid; Tayādhūq; Theodocus; Umayyad; medieval Islam.