A good starting point is the wikipedia entry.
Here is my take on it, after talking to numerous dancers, teachers, performers and musicians. I don't claim to have discovered a grand unifying theory, but I think the basics below make sense!
The Basic History
The basic idea, that I think most will agree to, is that salsa (as we know it today) is a fusion of the following:
- Traditional Latino Folk Dances/Music
- African Percussion, and the Rumba
- Spanish Wind and String instruments
The Jazz Influence
The first emergence of salsa (as we know it) came from Son (again, a mix of all three forms of music/instruments as listed above) in the early 1900s.
Son (and other similar types of Latin music) made their way into the US, via the Caribbean, throughout the 1900s. The first stop in the US was Miami (which naturally has a large Puerto Rican influence on the music), however, Cuban-styled clubs were established as far north as New York (Manhattan) and beyond.
With New York being known as the Jazz capital of the world, it was only a matter of time before the Jazz musicians mixed with the "jumping" Latino clubs (an economic depression didn't stop the Latinos partying!). I don't think it was a coincidence that Jazz and cuban son mixed together in the 1930s... if I was a Jazz musician working in the great depression of the 30s, I would certainly be going over to the latino clubs in my breaks to hang out and forget my troubles too. I hear this is how Cuban Son and Jazz were mixed... the net result is that piano, trumpets and all sorts of other Jazz and "big band" instruments were introduced to Son... which resulted in Salsa.
The Jazz Influence (part two)
Just as Son was "introduced" to the Jazz clubs in New York, I often then reflect on modern Cuban bands. Cuban bands (today) typically employ western-style drum kits, electric bass guitars, and so on. My guess is that just as Son made it's way up to North America, the musical instruments and styles also made their way back to Cuba and South America too.
The term Mambo is a confusing one. For this article, I refer to mambo as a Jazzy type of salsa, which was very common in the 1970s in New York, and has made a resurgence within the last five years in the Western salsa scene. So, I guess the net result of mixing Son and Jazz is mambo, which is just a particular type of Salsa.
Original proponents of Mambo include Tito Puente and Celia Cruz.
Many of the folk Latin percussion rhythms come from metaphores. Cumbia, so I am told, is very much a reflection of the rugged Andes moutain range (the music has an "up and down"
feel to it). The Caballo, a pattern sometimes used in salsa, has a very rythmical feel to it (for lack of a better term) - and Caballo translated to English means "horse". Makes sense!
When listening to different types of music, I tend to use the bass as telling descriptor for the origin of the music. More often than not, I find that strong bass lines indicate afro-origin styles of music. Weaker bass lines often indicate a traditional Latin folk origin.
Incidentally, Salsa is a very hard musical style to play. Musicians find salsa hard, and it takes a lot longer to master salsa than other related styles (cha cha, latin jazz, etc). Salsa music needs attitude, energy, and an ability to play slightly off the beat - or with "sabor"/"flavour" (perfect timing doesn't always seem to work for salsa).