Salsa represents a mix of Latin musical genres, but its primary component is Cuban dance music. The roots of salsa originated in Eastern Cuba from the Cuban Son (about 1920) and Afro-Cuban dance (like Afro-Cuban rumba).
Just wondering - are you seeking more information about the origins of Salsa?
I can tell you that whilst Cuban Son is indeed one of the roots of the dance, the way the dance has been since the 1950s is a syncretisation of Son with other dances as well. One of these is the Danzón. Another is Swing. Many elements have been borrowed from other dances.
Salsa, is not a purely Cuban dance. In fact the US and Colombia have had a major influence on its development.