Which composer had the most influence on classical music?
Hmm… I’m not quite sure how to answer this. All music is apparently influenced by music of an earlier person, so the only real way to answer this is to say that the person who first wrote any sort of music was the person who had the most influence on the music. Outside of that, going from plainchant to oratorios to Baroque instrumental music, while many would love to say Bach, I’m not sure if he was well known by that time or not. I don’t think one single composer had influence, but the aggregate whole led us into the style of music inside the classical era. Now, if you mean classical music as a “genre.” Then that’s pretty much an impossible question. Everyone influences everyone differently. Since music is so diverse today, There’s no one way to answer this question.