3rd-century Krorän and Niya on the southeast edge of the Tarim Basin contain loanwords and names that appear to come from a closely related language, referred to as Tocharian C. The discovery of Tocharian upset some theories about the relations of Indo-European languages and revitalized their study. In the 19th century, it was thought that the division between centum and satem languages was a simple west–east division, with centum languages in the west. The theory was undermined in the early 20th century by the discovery of Hittite, a centum language in a relatively eastern location, and Tocharian, which was a centum language despite being the easternmost branch. The result was a new hypothesis, following the wave model of Johannes Schmidt, suggesting that the satem isogloss represents a linguistic innovation in the central part of the Proto-Indo-European home range, and the centum languages along the eastern and the western peripheries did not undergo that change. Several scholars identify the ancestors of the Tocharians with the Afanasievo culture of South Siberia ( 3300–2500 BC), an early eastern offshoot of the steppe cultures of the Don-Volga area that later became the Yamnayans. Under this scenario, Tocharian-speakers would have immigrated to the Tarim Basin from the north at some later point. On this basis, Michaël Peyrot argues that several of the most striking typological peculiarities of Tocharian are rooted in a prolonged contact of Proto-Tocharian with an early stage of Proto-Samoyedic in South Siberia. Among others, this might explain the merger of all three stop series (e.g. *t, *d, *dʰ > *t), which must have led to a huge number of homonyms, as well as the development of an agglutinative case system. Most scholars reject Walter Bruno Henning's proposed link to Gutian, a language spoken on the Iranian plateau in the 22nd century BC and known only from personal names. Tocharian probably died out after 840 when the Uyghurs, expelled from Mongolia by the Kyrgyz, moved into the Tarim Basin. The theory is supported by the discovery of translations of Tocharian texts into Uyghur. Some modern Chinese words may ultimately derive from a Tocharian or related source, e.g. Old Chinese () "honey", from Proto-Tocharian *ḿət(ə) (where *ḿ is palatalized; cf. Tocharian B ), cognate with Old Church Slavonic (transliterated: ) (meaning "honey"), and English . Names A colophon to a Buddhist manuscript in Old Turkic from 800 AD states that it was translated from