Reggae developed from the Jamaican styles ska and rocksteady.
Ska emerged in Jamaica in the late 1950s and featured a brisk tempo, prominent horns, and guitar or piano accents on the offbeat. Rocksteady followed in the mid-1960s, slowing the rhythm and placing greater emphasis on bass lines and vocal harmonies.
Reggae took shape from these earlier forms during the late 1960s. Its sound commonly features a strong bass line, a steady drum pattern, and offbeat guitar or keyboard accents. The style became internationally associated with Jamaica through artists including Bob Marley and the Wailers.
Dancehall is a later Jamaican style that developed from reggae, while mento is an older Jamaican folk music tradition. Calypso developed primarily in Trinidad and Tobago, so these genres are related to Caribbean music but are not the direct answer.