It's said that if Italian-born British composer and pianist Muzio Clementi hadn't been alive at the same time as Haydn, Mozart and Beethoven, his name would be better known today. In fact, Beethoven admired his music. Clementi was in demand in London as a performer and composer, but he also started a piano building company that produced the most advanced pianos in the first half of the 1800s. A savvy businessman, he also started a music publishing business and, if he couldn't surpass Beethoven in talent, Clementi took advantage of their friendship and became the sole publisher of Beethoven's music in England.

Of an estimated twenty symphonies Clementi composed, he published only two in 1787. Autograph portions of his later unpublished symphonies, which include everything from sketches to complete movements, are in the Library of Congress and the British Library. With these, scholars have been able to reconstruct four. Catalogued without Opus Number as WoO 35, his "Symphony No. 4" in D was compiled from a legible copy of the first movement in England, and the remaining three movements in Washington, D.C. This symphony that is said to be his crowning musical achievement is today's Midday Masterpiece.

FYI:
Haydn 1732-1809
Clementi 1752-1832
Mozart 1756-1791
Beethoven 1770-1827