Bach isn't actually known much for a composer, which I don't gives him justice, but it's partially true. Most of Bach's work is theory study because he was showing the world how to understand music. I would say he's like Bruce Lee teaching the world martial arts, but bach introduced music understanding to the world. Before him it was strictly church study, I'm not a historian but I know that. He had some compositions Fugue in D minor and the brandenburg concertos (sc), but most of his compositions are theoritical. Still the godfather of modern music.