The fundamental lines of books on Bach's biography are unvaried over centuries, probably since Forkel. And the greatest difficulty of writing a new biography doesn't concern the problem of actual research, but the unsaid orientation on the chef d'oeuvre of Bach-research, the two volumes of Spitta's biography. For this Bach should be the protestant cantor 'kat'exochen', and his employments at courts are neglected.. Part 2 shows, that also the well-known facts on Bach and his biography could lead to a new view, if we neglect the very protestant stand-point of orthodox bach-scholarship and free ourselves from ideology and left conventions. The final part leads to a new approach to Bach's biography, not the 'external' life, working conditions or strategies of writing, devoting and publishing compositions. The question is to find out categories, which works of Bach are not only typical for him, in the sense of typical for his style, but typical for his behaviour, his religiousness, his understanding of confession or politics. Therefore as a 'sociological axiom' of art may suggest, that all art, even the most abstract motivic-thematic labour is a statement about the individual, who made it. So there is a biographical constellation - which doesn't mean the daily situation in a sense of simple hermeneutics - which is the condition for artistic practice. The problem is, to find ways from the music to the biography, from the aesthetical to the historical subject, or, methodologically, to come into this hermeneutical circle. This is possible by a close hearing, a hearing for pecularities, that is, certain expressions, which draw our attention, because they are not congruent to our experience and our preconception, developed on many examples from the same time or the same composer. Finally this approach is tested in cantata 19 'There arose a fight', and especially the aria 'Stay, you angels, stay with me!', which combines a solo voice with a cantus firmus in a trumpet. This combination is seen as Bach's genuine idea and interpreted in the horizon of his biography in 1726, when Christiana Henrietta Sophia, his first daughter from his marriage with Anna Magdalena, died. At last we have to take the question into consideration, how far the pecularities are a result of our preconception or our prefigured picture of a composer. This remains a problem, because everyone's perspective - including the scholar - is conditioned by circumstances, which can never be completely ruled out. But if we are conscious of this problem and the premises, which form our picture of Bach, there will be a real chance, to write a biography, which is more than ideology.