Kievan Rus (862-1242) was a medieval political federation located in modern-day Belarus, Ukraine, and part of Russia (the latter named for the Rus, a Scandinavian people). The name Kievan Rus is a modern-day (19th century) designation but has the same meaning as 'land of the Rus,' which is how the region was known in the Middle Ages. The Rus ruled from the city of Kiev (also given as Kyiv) and so 'Kievan Rus' simply meant "the lands of the Rus of Kiev". The Rus are first mentioned in the Annals of Saint-Bertin which records their presence in a diplomatic mission from Constantinople to the court of Louis the Pious (r. 814-840) in 839. The annals claim they were Swedes, and this is possible, but their ethnicity has never been firmly established. The story of the arrival of the Rus in the east is first told in the Primary Chronicle (also known as the Tale of Bygone Years, c. 12th century) of Russia. This work relates how the people of the land invited the Rus (identified as Scandinavian Vikings) to rule and maintain order in their country in the mid-9th century CE. Three brothers, including one named Rurik, accepted the invitation and founded the Rurik Dynasty which would last for over 700 years. This version of events is supported in the present day by historians who are labeled 'Normanists' (those who accept a Norse origin for the Rurikid Dynasty) and is challenged by so-called 'Anti-Normanists' who argue for a Slavic origin of Russia and the other states. The Normanist claims are presently considered more valid and it is generally accepted that the Norse leader Rurik (r. 862-879) founded the dynasty which would endure, in an unbroken line, through the reign of Ivan IV, first Tsar of Russia (r. 1547-1584) also known as Ivan the Terrible. The state of Kievan Rus fell to the Mongols between 1237-1242 CE, breaking the region in pieces which eventually developed into the modern states of Belarus, Russia, and Ukraine.
