Important composers in transitional eras?

Question

I understand Beethoven (and Schubert) to be very important composers in the transition from the Classical Era to the Romantic, such that they could be considered the first Romantic composers.Are there similar figures that can be pointed to at the start of the Baroque and Classical Eras? Are there individual pieces that are strongly representative of the change, comparable to Beethoven's 3rd and 5th symphonies?Big names I am aware of, such as Mozart and Haydn or J.S. Bach and Handel seem to have been working in a time when their respective eras had already been established.

Answer 1

CPE Bach and JC Bach significantly influenced Haydn and Mozart (respectively). Many of their compositions show elements of structure and the style galant. They are so often overlooked!