In the 8th century, Transoxiana, the territory between the Amudarya and Syrdarya rivers, was conquered by the Arabs (Qutayba ibn Muslim) becoming a focal point soon after of the Islamic Golden Age. Among the achievements of scholars during this period were the development of trigonometry into its modern form (simplifying its practical application to calculate the phases of the moon), advances in optics, in astronomy, as well as in poetry, philosophy, art, calligraphy, and many others, which set the foundation for the Muslim Renaissance.