The Digital Archives contains the unique collections of the Beethoven-Haus: Music manuscripts, first editions, letters and pictures.
[from the website's description]
By linking more than 5,000 documents on 26,000 coloured scans of high quality, 1,600 audio files (music examples, audio letters) and 7,600 text files, Beethoven's thinking, life and work become tangible and can be experienced in a visual and audible way. Portraits and topographical depictions show the composer and the world he lived in.