History of Ukraine
Strikingly different interpretations of the medieval state of Kievan Rus' appear in the four schools of historiography within Ukraine: Russophile, Sovietophile, Eastern Slavic, and Ukrainophile. The Sovietophile and Russophile schools have become marginalized in independent Ukraine, with the Ukrainophile school being dominant in the early 21st century. The Ukrainophile school promotes an identity that is mutually exclusive of Russia. It has come to dominate the nation's educational system, security forces, and national symbols and monuments, although it has been dismissed as nationalist by Western historians. The East Slavic school, an eclectic compromise between Ukrainophiles and Russophilism, has a weaker ideological and symbolic base, although it is preferred by Ukraine's centrist former elites.
Russian language
Judging by the historical records, by approximately 1000 AD the predominant ethnic group over much of modern European Russia, Ukraine and Belarus was the Eastern branch of the Slavs, speaking a closely related group of dialects. The political unification of this region into Kievan Rus' in about 880, from which modern Russia, Ukraine and Belarus trace their origins, established Old East Slavic as a literary and commercial language. It was soon followed by the adoption of Christianity in 988 and the introduction of the South Slavic Old Church Slavonic as the liturgical and official language. Borrowings and calques from Byzantine Greek began to enter the Old East Slavic and spoken dialects at this time, which in their turn modified the Old Church Slavonic as well.
Dialectal differentiation accelerated after the breakup of Kievan Rus' in approximately 1100. On the territories of modern Belarus and Ukraine emerged Ruthenian and in modern Russia medieval Russian. They became distinct since the 13th century, i.e. following the division of that land between the Grand Duchy of Lithuania, Poland and Hungary in the west and independent Novgorod and Pskov feudal republics plus numerous small duchies (which came to be vassals of the Tatars) in the east.