Luis Dias on Beethoven's business life:

Once Beethoven had poured his creative energy to the fullest into a composition, he regarded it as commercial property, deserving the best possible price on the most favourable terms. Of the hundreds of his letters that have survived, a major chunk deals with the mundane business of getting published: pitching a work, complaining about poor terms, bargaining, and correcting proofs. This is hardly surprising; he is perhaps the first composer whose income depended so much on being published, even more so after his crippling deafness gradually put an end to his career as a performer and to some extent as a teacher as well.