Bylina or Bylyna (Russian: были́на; pl. Russian: были́ны Byliny; Ukrainian: билина Bylyna; pl. Ukrainian: били́ни Bylyny) is a traditional East Slavic oral epic narrative poem. Byliny singers loosely utilize historical fact greatly embellished with fantasy or hyperbole to create their songs. The word Bylina is derived from the past tense of the verb “to be” (Russian: быть byt') and implies “something that was.” The term most likely originated with scholars of Russian folklore; in 1839, Sakharov, a Russian folklorist, published an anthology of Russian folklore, a section of which he titled “Byliny of the Russian People,” causing the popularization of the term. Later scholars believe that Sakharov misunderstood the word bylina in the opening of Igor’ Tale as “an ancient poem.” The folk singers of byliny called these songs stariny (Russian: старины) or starinki (Russian: старинки) meaning stories of old.

Most historians of East Slavic and Russian folklore believe that byliny as a genre arose during the Kievan period, during the tenth and eleventh century; byliny continued to be written till about the arrival of the Tatars in the thirteenth century and the destruction of the Old East Slavic civilization. Byliny incorporate elements of history from several epochs into their stories. For example, byliny singers refer to many of the enemies of the Kievan people as Tartars though the stories originally referred to other steppe peoples in conflict with Kievan Rus’. The character of Prince Vladimir refers to a generalized “epic Vladimir” rather than an allusion to a specific historical Vladimir.