On November 21, 2011, at the Far Eastern Studies Seminar organized by the Department of Far Eastern Studies of the IOM RAS, Dr A.A.Kovalyov, researcher at the Institute for the Complex Social Studies, St Petersburg State University, submitted his presentation, The Northern Border of the Tangut State of Xi Xia According to Archaeological and Written Sources [Северная граница тангутского государства Си Ся по археологическим и письменным источникам].

The presentation was based on the data acquired during an archaeological expedition to China and Mongolia that was joined by Dr A.Kovalyov. In Alashan desert, the expedition found two lines of walls with remnants of some military buildings along them. There were no archaeological materials that could help dating the site but radiocarbon analysis of wood used to build the walls and buildings showed that they must have been erected during 9th to 13th century. Since the Mongols did not need constructions of this type and their purpose was clearly to defend an invasion from the north make us conclude that they were probably built by the Tanguts. Thus, the northern border of Xi Xia could go through the southern part of the territory of modern Mongolia, much to the north of the commonly adopted line.