in the period 1700–1750, the trio sonata form became a sine qua non in the musical world. it incorporated all the ideals of harmony, melody and counterpoint espoused by theorists such as mattheson, scheibe and quantz. in his treatise "der vollkommene capellmeister" of 1739, mattheson wrote that, "... es müssen hier alle drey stimmen, jede für sich, eine feine melodie führen; und doch dabey, soviel möglich, den dreyklang behaupten, als obes nur zufälliger weise geschehe": "here each of the three voices must separately provide a fine melodic line; yet all the while together they must sustain as much as possible the three part harmony, as if by serendipity." amongst all composers of that era, bach was the one who raised the trio sonata form to its highest degree of perfection. in 1774 bach's son carl philip emmanuel commented that even after fifty years his father's compositions of this kind still sounded very good and that the lyricism of several of his adagios had never been surpassed. this continued veneration for these particular works even long after his death probably sprang not only from the fact that the form matched bach's own compositional ideals—that all voices should "work wondrously with each other" ("wundersam durcheinander arbeiten")—but also from the succeeding generation's preference for "sensitive" melodies. perhaps even more influential was bach's elevation of the harpsichord from a continuo instrument to a prominent obbligato instrument, on equal terms with the solo instrument, whilst also providing the bass line. as comments, with his sonatas for violin and obbligato keyboard "bach triggered off the gradual demise of the sonata for violin and continuo," even though it lived on in a few eighteenth century volin sonatas, for example those of bach's german contemporaries johann adam birkenstock, johann david heinichen, gottfried kirchhoff and johann georg pisendel.