And in this case, I really mean the early Classical period. The Six Grand Overtures of Johann Christian Bach, Op. 18 - three movement symphonies dating from the 1770s. And totally delightful too. J.C. Bach was one the first composers to establish deliberate thematic contrast between movements, a style that rapidly became a hallmark of the Classical style. You can hear a lot of J.C. Bach's approach in Mozart.
But sadly most people have heard Mozart, even if only Mozart's "Greatest Hits", and very few have heard Johann Christian Bach. Or his even more talented and adventurous brother, Carl Philipp Emmanuel Bach, who exerted equivalent influence on Haydn. I feel I am just scratching the surface of this period - these two sons of J.S. Bach dominate early Classical music but there are other composers of importance to explore. Haydn I know well already, and his early music fits right in here. Lovely stuff. Great pleasures await.