Beethoven hymn discovered
His version of Pange Lingua was noticed by Professor Barry Cooper written inside a sketchbook.
It is believed to have been written by Beethoven around 1820, according to the BBC, but Prof Cooper was the first to recognise its significance as a previously unknown work by the composer.
"I was very surprised when I found this - I didn't think he'd written anything like this," Prof Cooper said.
He speculated that it may have been played at the 1820 ceremony in which Beethoven's patron, Archduke Rudolph of Austria, became Archbishop of Olmutz.
It may have been overlooked until now because "it just looked like a series of notes", he said, according to the BBC.
He added: "He never composed any functional music at all - the only liturgical music he wrote was for the two great masses.
"So to find him writing simple functional music for an ordinary church service is extraordinary."