Kaspar Karl van Beethoven, Brief an Breitkopf & Härtel in Leipzig, Wien, 10. Oktober 1804, Autograph

Between 1802 and 1806 Karl van Beethoven organized the sale of his brother's works and also negotiated with music publishers. This is shown in particular by his extensive correspondence with Breitkopf & Härtel in Leipzig.

Härtel had declined to publish Beethoven's Oratorio "Christus am Ölberge" ("Christ on the Mount of Olives") op. 85 because he did not accept Beethoven's conditions. Instead of paying him money, he suggested paying him in sheet music. Karl writes back that he will think this over.

Furthermore Karl offers him five new works for a total sum of 1,100 florins: the Third Symphony op. 55, the Triple Concerto op. 56 as well as the three Sonatas opp. 53, 54 and 56 (which had not been completed at the time the letter was written). He stipulates the condition that he must also agree to a fixed publication date. Karl also enquires whether Härtel might be interested in two or three quartets. He is not able to deliver them immediately (op. 59 was only finished in 1806) but would reserve them for him if he is interested.