Kaval Sviri (Bulgarian: Кавал свири) whose title translates as “The Flute Plays” is a traditional Bulgarian folk song. A popular version was arranged by Petar Lyondev and performed by Ensemble Trakia of the Bulgarian State Television Female Vocal Choir, on the album Le Mystère des Voix Bulgares, Vol. II (album), released in 1988 on the Nonesuch label in the United States.
Popular belief holds that the song was used by composer Joseph LoDuca as the basis for Xena's fight theme in Xena: Warrior Princess, although the vocals that appear in the show's opening sequence sing different lyrics.
The song is also sampled in Austrian Neue Deutsche Härte band Stahlhammer's song Stahlingrad, from the 1997 album Wiener Blut. The song has been performed by choirs around the world, including a popular version by the Yale Slavic Chorus, although their video incorrectly attributes the arrangement to another famous Bulgarian composer, Filip Kutev.