The working draft of the four famous string quartets, Opus 50, Numbers 3, 4, 5, and 6, which are bound together in a book, are extremely rare and throw light on the composing process.
They were first discovered in 1982 when the owner, who wishes to remain anonymous, took them in a shopping bag to show experts at a Haydn festival in her home city of Melbourne, Australia.
She is understood to have known what the manuscript was because it had been in her family for more than a century. What she did not know was that her version of the string quartets was unknown to scholars and considered lost.
When she was told about the value of her possession, it was transferred to a bank for safekeeping. At the beginning of this year, she decided to sell. The auction takes place at Sotheby's on 18 May, with an estimate of up to £750,000 for the four quartets.
The owner said in a statement: "They are not doing anybody any good in a bank vault. My husband and I have been music fans all our lives and I would like to establish a trust to help young people with talent make their way in the music world."
Stephen Roe, Sotheby's music specialist, said the manuscripts differed in small but significant details from the version which Haydn published in 1787.
"There are additional bars and crossed-out bars. The draft shows how the composer got to his final version. A lot of the movement titles are different, for example: in one movement he substituted `allegro' for `allegretto' in the published version."
The manuscripts have had a chequered history since they were written by the Austrian composer in the mid-1780s.
It is thought that Haydn gave them to his friend Muzio Clementi, the Italian composer, who made annotations. They came into the present owner's family in 1851 when they were bought in London by her ancestor, a retired English colonel, before he and his family emigrated to the Antipodes.
In the 19th century they languished on a sheep farm in New Zealand and survived a crossing by ship to Australia.Reuse content