Bylina (Russian: были́на) is a traditional epic, heroic narrative poetry of early East Slavs of Kievan Rus, the tradition continued in Russia and Ukraine.
Bylina comes from the Russian "byl'" (быль), a word which signifies a story of real events, as opposed to a fictional one and a cognate of the English verb to be.
Bylinas are kind of poetry without rhyme (blank verse), but with a characteristic rhythm, a kind of free verse. Most of bylinas were preserved in northern regions of Russia, and their style was imitated by several famous Russian poets.