The attention that Johann Nepomuk Hummel gave to the repertoire of transcriptions was significant throughout his career. A huge part of his production, about fifty compositions, were to be arranged by him for piano, flute, violin and cello; these transcriptions were of various musical genres, from opera to symphonies and chamber music. The most considered was the symphonic repertoire with 18 arrangements: with the exception of only one symphony by Andreas Romberg, Hummel's efforts were projected mainly to the three great masters of the past: Mozart (six symphony transcriptions), Haydn (four) and Beethoven (seven). It's interesting to note that, on the contrary, Hummel only transcribed piano concerti by Mozart. In order to understand this choice, it is necessary to consider the evolution of certain elements that, between the 18th and 19th centuries, were changing significantly. Elements that conditioned the whole musical situation in Europe were things such as: the editorial market, the evolution of the piano concerto genre, the varied status of Mozart's concerti as standard, performed repertoire, and finally the physical evolution of the piano itself. Furthermore, Hummel's contribution is particularly interesting in relation to his efforts to complete Mozart's text in line with standard 18th century performance practice, in situations where Mozart's notation is often sparse or lacking comprehensiveness (for example, in the difficult case of improvised embellishment). [ABSTRACT FROM AUTHOR]