At its greatest extent, in the mid-11th century, it stretched from the White Sea in the north to the Black Sea in the south and from the headwaters of the Vistula in the west to the Taman Peninsula in the east, uniting the majority of East Slavic tribes. The Rurik dynasty would continue to rule parts of Rus' until the 16th century with the Tsardom of Russia. The modern nations of Belarus, Russia, and Ukraine all claim Kievan Rus' as their cultural ancestors, with Belarus and Russia deriving their names from it. Kievan Rus' ( Old East Slavic: Роусь, romanized: Rusĭ, or роусьскаѧ землѧ, romanized: rusĭskaę zemlę, 'Rus' land') or Kyivan Rus', was a loose federation of East Slavic, Baltic and Finnic peoples in Eastern and Northern Europe from the late 9th to the mid-13th century, under the reign of the Rurik dynasty, founded by the Varangian prince Rurik.
