Joseph Haydn's sheet music manuscripts (partially lost music sheets; 18th-19th century)
Joseph Haydn is one of the most prolific composers of the Classical Era. With well over 100 symphonies, several concertos written for various instruments, and a few operas to his name, the library of his work has proven quite difficult to keep accounted for. He was a friend of Mozart's and a teacher of Beethoven. He continued to work well into his old age and up to his death garnering the nickname "Vater Haydn" or in English "Papa Haydn."
In 1979, Esterhaza, the opera house of which he worked was set on fire and many of his non-widely published works were destroyed. Every once in a great while, a work is discovered in a score copy, but many are feared to be forever lost. While his operas and symphonies remain mostly intact, a vast majority of his string quartets, concertos, and piano pieces are yet to be found. His most famous concerto, the one for Double Bass in D Minor only has 2 measures surviving.