The two compositions -- a concerto in G and a prelude in G -- have long been in the files at the International Mozarteum Foundation in Salzburg, Austria, as anonymous works and were even published in the book 'New Mozart Edition' in 1982.

Now Ulrich Leisinger, director of the foundation's research department, believes the works actually were composed by Mozart before he was old enough to write music, and that Mozart's father, Leopold, transcribed them.

The foundation said in a statement that Leisinger analyzed the handwriting and other 'stylistic criteria' to determine the music was 'almost certainly unknown compositions by' the young Mozart.

The compositions were found in a book, compiled by Mozart's father, that was used for practice and the musical education of both Mozart and his sister, according to the statement.

Leisinger's analyses 'support the claim that they were actually composed by the young Mozart, who was not yet versed in musical notation, and transcribed by his father as the boy played the works at the keyboard,' the statement said.