traditional form of Old Russian and Russian heroic narrative poetry transmitted orally, still a creative tradition in the 20th century. The oldest byliny belong to a cycle dealing with the golden age of Kievan (Kiev) Rus in the 10th–12th century. They centre on the deeds of Prince Vladimir I and his court. One of the favourite heroes is the independent Cossack Ilya of Murom, who defended Kievan Rus from the Mongols. Although these ancient songs are no longer known to the peasants around Kiev, they were discovered in the 19th century in the repertoire of peasants living around Lake Onega in the remote northwestern regions of European Russia. They are also known in the far northeastern outposts of Siberia.

Other byliny, dealing with all periods of Ukrainian and Russian history, have been collected throughout the country. They may relate events from the reigns of Ivan the Terrible or Peter the Great, or deal with the Cossack rebels Stenka Razin and Pugachov. A 20th-century bylina, the Tale of Lenin, converts the chief events of the Russian Revolution into a formulaic hero tale. Taken together, the byliny constitute a folk history in which facts and sympathies are often at variance with official history.

Byliny may have originated with professional court minstrels, but they are now circulated and created by peasants and simple folk. With the spread of literacy, the art of composing and chanting byliny is dying out.