Joseph Haydn, often called the "Father of the Symphony" and the "Father of the String Quartet," was a pivotal figure in the development of classical music. Here are ten interesting facts about this prolific and influential composer: 1 - Prolific Output: Haydn composed 104 symphonies, 68 string quartets, 32 piano trios, 14 masses, and numerous other works including operas and concertos. His extensive output helped define the classical style and set a standard for future composers.