Timur initiated the last flowering of Transoxiana by gathering together numerous artisans and scholars from the vast lands he had conquered into his capital, Samarqand, thus imbuing his empire with a rich Perso-Islamic culture. During his reign and the reigns of his immediate descendants, a wide range of religious and palatial construction masterpieces were undertaken in Samarqand and other population centres. Amir Timur initiated an exchange of medical discoveries and patronised physicians, scientists and artists from the neighbouring regions such as India; His grandson Ulugh Beg was one of the world's first great astronomers. It was during the Timurid dynasty that Turkic, in the form of the Chaghatai dialect, became a literary language in its own right in Transoxiana, although the Timurids were Persianate in nature. The greatest Chaghataid writer, Ali-Shir Nava'i, was active in the city of Herat (now in northwestern Afghanistan) in the second half of the 15th century.