In the late 19th century, while the rest of America was stomping their feet to military marches, and New Orleans was dancing to VooDoo rhythms. New Orleans is the birthplace of Jazz, an “energetic or vigorous” mixture of African and Creole rhythms with European styles and instruments.

More evidence of early Jazz was produced by Papa Jack Laine’s band in New Orleans circa 1885 when it was noted that he played with a “ragged time,” which meant the musicians were playing variations on the tempo to make it “swing.” Irishman Papa Jack Laine’s Reliance Brass Band was the training ground for many of the musicians, white, black and creole, who went on to pioneer Jazz in their own ensembles.

Source: http://www.neworleansonline.com/neworleans/music/musichistory/jazzbirthplace.html