The Tale of Bygone Years (, "Pověstĭ vremęnĭnyxŭ lětŭ"), known in English-language historiography as the Primary Chronicle or Russian Primary letopis or, after the author it has traditionally been ascribed to, "Nestor's letopis or The letopis of Nestor", is a history of the Kievan Rus' from about 850 to 1110, originally compiled in Kiev about 1113. The work’s name originates from the opening sentence of the text, which reads: “These are the narratives of bygone years regarding the origin of the land of Rus’ (Old East Slavic: Рѹсь), the first princes of Kiev, and from what source the land of Rus’ had its beginning.” The work is considered to be a fundamental source in the interpretation of the history of the East Slavs. The "Chronicle's" content is known to us today from several surviving editions and codices that have been revised over the years and evince a slight degree of variation from each other.