Excerpts from Books and Wikipedia
"By 945, the Rus had grown some visible roots. They had a capital, a prince, and at least the semblance of a central government: Igor, prince of Kiev, had enough power to swear out a treaty on behalf of his people with Constantine Porphyrogenitus. . . . Right after signing the treaty, Igor met the death of a tribal chief. . . . His wife Olga took over as regent for their son Svyatoslav. . . . In 957, Olga made a state visit to Constantinople, where Constantine received her as a fellow sovereign. . . . At the end of her visit, she agreed to be baptized. . . . In less than half a century, the Rus had progressed from their wooden shelters by the Volga to the royal reception halls of Constantinople. It was a extraordinarily fast metamorphosis--and it proved to be partly temporary. In 963, Igor's son Svyatoslav took power in his own name, at the age of twenty-one. His mother Olga retired from public life and spent her time trying to talk her fellow Rus into accepting Christianity. . . . He spent the first years of his solo rule fighting against the Khazars, the Slavic tribes, and the Turkish nomads called Pechenegs on his east, as Olga's dream of a Christian people receded." [Bauer; Medieval World, p. 531-3] In 862 Rurik founds the Viking state of Russia., first in Novgorod, then Kiev. "Would be sustained until the Mongol invasion of Rus' over four and a half centuries, despite peaking during the middle 11th century during the reign of Yaroslav the Wise." [Wikipedia: Timeline of Middle Ages]