Chosen as a capital by Abaqa Khan, fourth ruler of the Ilkhanate, for its favored location in the northwestern grasslands, in 1295, his successor Ghazan Khan made it the chief administrative centre of an empire stretching from Anatolia to the Oxus River and from the Caucasus to the Indian Ocean. Under his rule, new walls were built around the city, and numerous public buildings, educational facilities, and caravansarais were erected to serve traders travelling on the ancient Silk Road. The Byzantine Gregory Chioniades is said to have served as the city's Orthodox bishop during this time.