Roots music
The music we call Jazz today originated in African American communities and evolved out of American Roots music and the Blues and often included instruments like Fiddle and Mandolin that are now more commonly associated with Folk or Roots music. Modern acts such as Clannad, Nightnoise, Melanie O'Reilly, and Raggle Taggle or Roland Becker (in the eighties) combine Celtic music with jazz. The jazz can range from the big band swing style to the smooth jazz style.