Swamp blues, sometimes
the Excello sound, is a subgenre of
blues music and a variation of
Louisiana blues that developed around
Baton Rouge in the 1950s and which reached a peak of popularity in the 1960s. It generally has a slow tempo and incorporates influences from other genres of music, particularly the regional styles of
zydeco and
Cajun music. Its most successful proponents included
Slim Harpo and
Lightnin' Slim, who enjoyed a number of national
rhythm and blues hits and whose work was frequently covered by bands of the
British Invasion.