John Weeks Moore, Complete Encyclopaedia of Music… (1880)
“ Bach, Johann Christoph, was probably one of the greatest contrapuntists and most expert organists in Germany towards the close of the seventeenth century. He was court and town organist at Eisenach. In the archives (as they were called) of the Bach family, which Emmanuel Bach possessed in Hamburg, there was, among other pieces, a motet of Johann Christoph's composition, in which he had ventured to make use of the extreme sixth, which, in his days, was considered an extremely bold attempt. ”
