Kyi, Shchek and Khoryv were three legendary brothers—often mentioned along with their sister Lybid' —who, according to the Primary Chronicle, founded the medieval city of Kyiv, which eventually became the capital of Kievan Rus' and present-day Ukraine. There is no precise and historically established information about the rule of Kyi and the establishment of the city of Kyiv.

The Russian Primary Chronicle, commonly shortened to Primary Chronicle, is a chronicle of Kievan Rus' from about 850 to 1110. It is believed to have been originally compiled in or near Kiev in the 1110s. Tradition ascribed its compilation to the monk Nestor beginning in the 17th century, but this is no longer believed to have been the case.