The Bodleian Libraries have been donated a rare autograph from composer Johann Sebastian Bach.

The manuscript of Bach's cantata for Ascension Day: 'Auf Christi Himmelfahrt allein' (BWV 128) is one of only four in the UK in the hand of the legendary composer.

The gift has been accepted via the Acceptance in lieu scheme to offset inheritance tax, and it has been allocated to the Bodleian.

The manuscript will be publicly displayed from March 15 at the Weston Library’s Treasury.

The donation was originally owned by collector Ralph Kohn, and is known as the 'Kohn manuscript'.

It provides a detailed insight into one of Bach's best cantatas, and despite slight erosion around the edges, it is regarded as one of the best-preserved Bach autographs.

Richard Ovenden, Bodley’s Librarian, said: "The Bodleian has collected music in a serious way since its foundation over 400 years ago, but a significant manuscript in the hand of one of the greatest composers of all time, Johann Sebastian Bach, has eluded us, until now."

Bach's compositions proved significant to the evolution of Western music.

With the vast majority of his works never published during his lifetime, the existence and survival of his autographs are critical in maintaining the memory of his musical grandeur.

Bach’s finest manuscripts are mostly found in Berlin, Leipzig and institutions in Germany, Poland, and the USA.

Only three other Bach autographs exist in the UK.

There are two at the British Library and one at the Fitzwilliam Museum in Cambridge.

Martin Holmes, Alfred Brendel Curator of Music at Bodleian Libraries, said: "It must be every music librarian’s dream to be given custody of a Bach autograph and the library is honoured to have been entrusted with this magnificent manuscript.

"Only two other institutions in the UK have Bach autographs in their collections and the Bodleian is proud to be the third."

Lord Parkinson of Whitley Bay, Minister for Arts and Heritage, said: "I’m delighted that this magnificent and important score can be shared with scholars and the public.

"Seeing how Johann Sebastian Bach set down his genius on the page will help to deepen our appreciation and understanding of the great composer, whose work continues to move people around the world three centuries after he wrote it."

Plans are also underway for a performance commemorating the tercentenary of the original performance of the cantata in 1725.

The manuscript, previously exhibited at Buckingham Palace, forms a significant part in the UK's manuscript curation history.

It will join Bodleian’s Special Collections music archive and continue to influence Bach study, performance, and appreciation in Oxford.