Concerto that Mozart penned for pupil to be aired after 200 years

Mozart wrote one of his most popular piano concertos for the daughter of a tax collector, it was revealed today.

The composer created Piano Concerto No23 for Barbara Ployer, an acclaimed pianist and the daughter of a merchant and tax collector living in Vienna, according to new research.

Documents taken to Poland during the Second World War indicate the piece was written for his former pupil after one of the manuscripts was found to contain embellishments in her handwriting.

The piece will be performed with Ms Ployer's changes at the Southbank next week for the first time in 200 years. Robert Levin, a pianist and musicologist, looked at manuscripts stored in Paris, Krakow and Berlin. He found that Mozart had started sketching the manuscript of Concerto No23 onto another containing cadenzas for Concerto No12 and discovered similarities between both concertos. Usually Mozart wrote cadenzas - passages where the soloist could show their prowess - after the original concertos. Mr Levin claims the composer wrote the cadenzas for Concerto No23 at the same time as the piece, proving he was writing it for someone rather than himself.

He said: "You can tell the cadenza was written at the drafting stage of the concerto because of the ink colour. Mozart bought the ink at the chemist in small amounts and as the quills get stubbier, they are thrown away, so you can see the order in which he does things.

"He wrote in the first violin part and bass together with the second violin, then switches to the piano part and writes out the cadenza."

The papers linking Concertos No12 and 23 date from 1786. Mr Levin said: "Barbara Ployer goes mad with her spraycan. Her solo part is brim full of the notes. It was written by her but she would have known how much he would have wanted her to write in." The only known "portrait" of Ms Ployer was sketched by Mozart, on a score.

Levin will perform the piece at Queen Elizabeth Hall on October 4.