What was the medieval state of Kyivan Rus, and was it a Russian or Ukrainian polity?
In existence from the ninth through the thirteenth centuries, Kyivan Rus was the first East Slavic polity; today it is claimed by Ukrainians, Belarusians, and Russians as the foundation of their respective state traditions.
The irony in this contest for historical primacy is that the mighty medieval state in question was actually created by the Varangian or Norman invaders, who came to rule over autochthonous East Slavs by advancing from the shores of the Baltic Sea down the Dnipro River sometime in the mid-ninth century. For a century or so, the rulers preserved Scandinavian names and close contacts with their homeland, but they eventually assimilated into the local Slavic culture. Kyivan Rus prospered thanks to its location on the trade routes from Northern Europe to the Byzantine Empire; it was from the latter, the major power of the time, that the young state adopted its religion, as well as its political and cultural models.Around 988, Prince Volodymyr the Saint (or Vladimir in modern Russian, a popular East Slavic first name ever since, including Lenin's and Putin's) accepted the Byzantine version of Christianity as a state religion. In addition to fostering the state's consolidation, the new religion meant the promotion of literacy in Old Church Slavonic, a bookish language based on the Cyrillic alphabet, which the Byzantine missionaries Cyril and Methodius had devised for the Slavs. Accepting Christianity in the form of the Easternrite Orthodox Church soon proved to be a momentous cultural choice, when the rift between Catholicism and Orthodoxy became formalized in the eleventh century. However, Kyivan Rus was never isolated from Central and Western Europe, either before or after the religious schism. Kyivan princes concluded alliances with and declared wars on their European neighbors, and Volodymyr's son Yaroslav married off his daughters to the kings of France, Hungary, and Norway.
The East Slavic population of Kyivan Rus did not possess a modern ethnic identity. Ordinary people thought of themselves as locals and Christians, while surviving literary sources also feature the concept of the “Rus land” as an object of premodern patriotism. Territorially, Kyivan Rus was centered in what is now Ukraine, but it also included significant parts of Belarus and European Russia; the present-day Moscow region was a frontier in the process of colonization. Moscow, which is first mentioned in the chronicles under the year 1147, was then no more than a village with a wooden stockade. The bookish language of the time, Old Church Slavonic, cannot be used as a marker of ethnic identity either, because it is genetically as close to modern Serbian and Bulgarian as it is to Ukrainian or Russian. Ordinary people likely spoke East Slavic dialects that in the south would be related to modern Ukrainian and, in other parts of the very large Rus state, to modern Belarusian and Russian.
Europe's largest state in terms of territory, Kyivan Rus was a loose federation of principalities governed by the princely Riurikid family (from the name of its legendary Norman founder, Riurik). Once members of the family stopped moving from one princely seat to another in the order prescribed by the complicated seniority system, local dynasties became entrenched and political fragmentation ensued. By the late twelfth century, Kyiv had lost its importance as a national center. Less than a century later, the invading Mongol army easily overcame the princes one by one and incorporated the Rus principalities into the gigantic Mongol empire. In the northeast the rulers of Vladimir-Suzdal and eventually the princes of Moscow would rise to prominence as the most reliable tax collectors on behalf of the Mongols, before challenging their masters in the late fourteenth century. To the west, another ascending Eastern European power, the Grand Duchy of Lithuania, took control of the former lands of Kyivan Rus.
It was only with the advent of modern nationalism in the nineteenth century that historians began claiming the Rus legacy for their ethnic groups. From the Russian point of view, there was an institutional and dynastic continuity from Kyivan Rus to the modern Russian state. Ukrainian historians have countered that their people were the most direct descendants of the Rus population. For as long as Kyiv remained part of the Russian Empire and the Soviet Union, Russian historians could keep presenting the Rus heritage as either Russian or as a common historical legacy of the three fraternal East Slavic peoples. Ukraine's declaration of independence in 1991 presented a direct threat to Russian historical mythology. The ancient capital of the “Russian” state, its first monasteries, and the graves of legendary knights were now in Ukraine. Under Putin, Russia has tried to compensate for the “loss" of its Kyivan heritage by intensifying archaeological explorations in the northwestern regions of Novgorod and Ladoga, but Kyiv has not lost its special place in Russian historical memory.