Kievan Rus' (Old East Slavic: Рѹ́сь (Rus'), Рѹ́сьскаѧ землѧ (Rus'skaya zemlya), Ancient Greek: Ῥωσία, Latin: Rus(s)ia, Ruscia, Ruzzia, Rut(h)enia, Old Norse: Garðaríki) was a loose federation of East Slavic tribes in Europe from the late 9th to the mid-13th century, under the reign of the Rurik dynasty. The modern peoples of Belarus, Ukraine, and Russia all claim Kievan Rus' as their cultural ancestors. At its greatest extent in the mid-11th century, it stretched from the Baltic 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...

As part of the Mongol invasion of Europe, the Mongol Empire invaded Kievan Rus' in the 13th century, destroying numerous cities, including Ryazan, Kolomna, Moscow, Vladimir, and Kiev. The campaign was heralded by the Battle of the Kalka River in May 1223, which resulted in a Mongol victory over the forces of several Rus' principalities. The Mongols nevertheless retreated. A full-scale invasion of Rus' by Batu Khan followed, from 1237 to 1240. The invasion was ended by the Mongol succession process upon the death of Ögedei Khan. All Rus' principalities were forced to submit to Mongol rule and became...