Ancient Buddhist and Hindu states which ruled Bangladesh included the Vanga, Samatata and Pundra kingdoms, the Mauryan and Gupta Empires, the Varman dynasty, Shashanka's kingdom, the Khadga and Candra dynasties, the Pala Empire, the Sena dynasty, the Harikela kingdom and the Deva dynasty. These states had well-developed currencies, banking, shipping, architecture, and art, and the ancient universities of Bikrampur and Mainamati hosted scholars and students from other parts of Asia. Xuanzang of China was a noted scholar who resided at the Somapura Mahavihara (the largest monastery in ancient India), and Atisa travelled from Bengal to Tibet to preach Buddhism. The earliest form of the Bengali language began to emerge during the eighth century. Early Muslim explorers and missionaries arrived in Bengal late in the first millennium CE. The Islamic conquest of Bengal began with the 1204 Ghurid expeditions led by Muhammad bin Bakhtiyar Khalji. Bengal was then ruled by the Delhi Sultanate for a century by governors from the Mamluk, Balban, and Tughluq dynasties.