 He is most famous for creating the one drop rhythm in the late 1960s; this beat places kick/snare emphasis on the third beat within a highly syncopated 4/4 bar.One Drop, an outgrowth of the ska and rocksteady, became the foundation for reggae music, combined with traditional Jamaican forms such as mento, burro and kumina.Grennan was also responsible for importing the "Flyers" beat to the United States – a beat which he had developed and recorded in the 60s in Jamaica.