At its core, klezmer has always been wedding music. Weddings were an enormously important part of life in Eastern European Jewish communities. Life was difficult in the Pale, and weddings gave people a reason to celebrate, and they tended to be large affairs. A wedding wasn't a wedding without klezmer music, which provided a frenetic and happy soundtrack to the party. But more than simply providing pleasant background music, most klezmer music was intended for dancing. Ritualistic dances were a central part of traditional Jewish weddings in Eastern Europe, and klezmer rhythms provided the beat and melody for those dances.
According to musicologist Walter Zev Feldman, the Old World klezmer repertoire consisted of four distinct categories: the core repertoire (Jewish rituals and dances), the transitional repertoire (non-Jewish tunes), the co-territorial repertoire (local, non-Jewish songs), and the cosmopolitan repertoire (popular Western and Eastern European dance music) [source: Rogovoy].
In the core repertoire, the most common type of song was the freylekhs, a generally happy dance song that used melodies from Jewish religious music. Freylekhs songs include the sher, or scissors dance, which is a type of mid-tempo Russian-style square dance; the khosidl, which is a slower dance; and the terkisher, which is similar to the tango. The klezmer core repertoire also included non-dance ritual songs, like holiday songs. The non-Jewish songs that would make up the rest of the klezmer repertoire included a wide variety of non-religious songs that a klezmer musician might have learned in his travels, including Romanian, Polish and Ukrainian dance songs, as well as slower songs of lamentation.
Klezmer was never limited to traditional or regional music, though. In the same way that a DJ might mix top 40 hits with more traditional music at a contemporary wedding, klezmorim always included non-Jewish popular music of the day in their repertoire. Popular Western European dances, like the polka and the waltz, were commonly played by klezmer musicians [source: Rogovoy].