Traditional
Norwegian type of song.
A stev is supposed to have four lines per verse and a steady rythm often marked by the singer by stomping. It is known to go back to the Viking ages (~1000 AD). It was often improvised and used in gatherings, where one person would sing a verse, and another person answer. Just like most Norwegian folk culture, stev was not written down before the National Romantic Period at the end of the 19th century.
Sources:
Norsk Folkemusikkatalog, http://www.folkogdans.no/nfk/ (Norwegian Folk Music Catalog)
An article in Dagbladet, http://www.dagbladet.no/kultur/1998/11/08/139064.html ("The Daily Magazine")