The Western Xia 西夏, to the Mongols the Tangut Empire, ruled Northwestern China from c. 1038 AD to c. 1227 AD. The early capital was established in Ningxia Province. By the beginning of the 12th century AD the power had shifted from the Tangut over to the Kharakhoto, causing the capital city's destruction in 1227 by the Mongols who then founded the Mongol Empire. Along with its political entity most of the written records and architecture of the Western Xia was destroyed. Therefore, its founders and history remained obscure until the 20th century. The Western Xia occupied the area round the Hexi Corridor, a crucial stretch to control the Silk Road during the reign of the Liao, the Jin, and the Southern Song. They also had significant achievements in literature, art, music, and architecture. Their extensive stance among the other empires of that era was especially attributable to their effective military organizations that integrated cavalry, chariots, archery, shields, artillery, cannons carried on the back of camels, and amphibious troops for combat to the land and to the water ways.