The Torghuts have been known since the times of Chingis Khan who highly valued them. In Chingis Khan's army the Torghuts protected his palaces and the nobility. According to historian Pavlov, the word torghut derives from torg meaning 'silk'. The migration of the ancestors of the Kalmyks westward in the 17th century was difficult. When they were crossing western Siberia, the majority of them were Torghuts and Derbets. Khoshuds were a minority. When these tribes settled between the rivers of Yaik and Don, they came to be known as Kalmyks. The Kalmyks are the only people who voluntarily became subjects of Russian Empire.