The first known mention of Siberia in Russian literature comes from a piece written in 1407 telling the account of a Tartar by the name of Khan Tokhtamysh who was murdered “in the Siberian lands”. Additionally, there are earlier Novgorod chronicles of expeditions into a place called Ugria, which appears to be the early name for the region of Siberia. The Grand Duke of Moscow would eventually conquer Novgorod and therefore inherit any lands that the Novgorods had taken in Siberia, though a vast part of the region was still under the control of local Tartar Khans. Some would serve as vassals for the Russian Tsars while others refused, and there was a bit of back and forth for some time relating to who really controlled the Siberian lands.