How did Carl Philipp Emanuel Bach help the transition from Baroque to Classical sonatas?

Carl Philipp Emanuel Bach was a pivotal figure in the evolution of the sonata, serving as a primary bridge between the Baroque era and the Classical period.12

His contributions to this transition included:

• Emphasis on Dramatic Contrast: Unlike the continuous, unitary processes of Baroque counterpoint, C.P.E. Bach embraced dramatic contrast. He placed significant stress on key contrast not only between movements but, crucially, within them.2
• Art of Transition: He placed a new, deliberate emphasis on the art of transition, which became a foundational element in the development of sonata-allegro form.12
• Empfindsamer Stil: As a leader of the empfindsamer Stil (or "sentimental style"), he sought to express a variety of deeply felt, mercurial emotions within his works. By juxtaposing phrases and sections of highly contrasting moods, he moved away from Baroque profundity toward a more personal, expressive musical language that anticipated the Romantic period.134

His keyboard sonatas, symphonies, and concerti were highly influential, directly impacting the development of the form for composers such as Joseph Haydn, W.A. Mozart, and Ludwig van Beethoven.1