Composers That Made up the Viennese School
The three composers that are considered to be the "founding fathers" of the Viennese School are Mozart, Haydn, and Beethoven. These composers studied together, often with one taking lessons from one of the others. Mozart took lessons from Haydn when he was still a young aspiring musician. Likewise, Beethoven sought to take lessons from Mozart. When that did not work out quite as successfully as he had hoped, Beethoven was taught by Haydn.
Mozart, Haydn, and Beethoven are known for the similarities in their musical style. They all seemed to follow a set of basic rules, which greatly differed from the rules currently in place during their time. These and other musicians/composers are responsible for the changes made to music during the Classical Period, but these three men are the ones who made those changes famous throughout history.