Zhangye is in the center of the Hexi Corridor. The area was the frontier for much of China's history, forming a natural passage to the Central Asian portion of the empire. During the Western Han dynasty, Chinese armies were often engaged against the Xiongnu in this area. It was also an important section of the Silk Road. The fearsome Mongol Emperor Kublai Khan is said to have been born in the Dafo temple, also the site of the longest reclining wooden Buddha in China. The city was formerly known as Ganzhou, a name retained both in the municipal region seat Ganzhou District and the Gan of the province of Gansu. In The Travels of Marco Polo, Marco Polo describes spending a year in a city called Campichu, which has been identified with Ganzhou (Zhangye).