There was a lot of American influence in Jamaica after WWII. Southern blues and jazz were heard a lot on radios that were a relatively new media at the time. This influence created Ska.
In the 1950s, Ska formed. It is an early ancestor of Reggae and rocksteady.
Ska is a slower version of Reggae with the stress on the offbeat.
In the 1970s, Ska became popular in Britain. The musicians would wear clothes with a black and white checker pattern. This signified the white and black influences of the music.