Our knowledge about Johann Sebastian Bach is as little as about no other classical composer. Related to a research project funded by the Gerda Henkel Stiftung the Leipzig Bach Archive now tries to unveil the secrets of the Thomaskantor by a new approach to research: What told the Thomaner about their teacher. A recently discovered matriculation register of the St. Thomas School from Bach’s days is the base for many new insights. A film by Peter Prestel