first theory of the origin of the Ukrainian language was suggested in Imperial Russia in the middle of the 18th century by Mikhail Lomonosov. This theory posits the existence of a common language spoken by all East Slavic people in the time of the Rus'. According to Lomonosov, the differences that subsequently developed between Great Russian and Ukrainian (which he referred to as Little Russian) could be explained by the influence of the Polish and Slovak languages on Ukrainian and the influence of Uralic languages on Russian from the 13th to the 17th centuries. Another point of view was developed during the 19th and 20th centuries by other linguists of Imperial Russia and the Soviet Union. Like Lomonosov, they assumed the existence of a common language spoken by East Slavs in the past. But unlike Lomonosov's hypothesis, this theory does not view "Polonization" or any other external influence as the main driving force that led to the formation of three different languages (Russian, Ukrainian and Belarusian) from the common Old East Slavic language. The supporters of this theory disagree, however, about the time when the different languages were formed. Soviet scholars set the divergence between Ukrainian and Russian only at later time periods (14th through 16th centuries). According to this view, Old East Slavic diverged into Belarusian and Ukrainian to the west (collectively, the Ruthenian language of the 15th to 18th centuries), and Old East Slavic to the north-east, after the political boundaries of the Kievan Rus' were redrawn in the 14th century. Some researchers, while admitting the differences between the dialects spoken by East Slavic tribes in the 10th and 11th centuries, still consider them as "regional manifestations of a common language". In contrast, Ahatanhel Krymsky and Aleksey Shakhmatov assumed the existence of the common spoken language of Eastern Slavs only in prehistoric times. According to their point of view, the diversification of the Old East Slavic language took place in the 8th or early 9th century. Russian linguist Andrey Zaliznyak stated that the Old Novgorod dialect differed significantly from that of other dialects of Kievan Rus' during the 11th–12th century, but started becoming more similar to them around 13th–15th centuries. The modern Russian language hence developed from the fusion of this Novgorod dialect and the common dialect spoken by the other Kievan Rus', whereas the modern Ukrainian and Belarusian languages developed from the dialects which did not differ