Unfortunately there are no reliable accounts of Gluck's first stay in Vienna and the nature of his study there, but without doubt his part in the musical life corresponded with the peculiar kind of training he had previously received. An important fact remarked by A. L. Marx ("Gluck und die Oper," I., 20) is that up to this time Gluck had held aloof from the piano, "that curious instrument which is unsatisfactory in every tone, and in melody suffers by comparison with every other, which is yet the blessed parent of creative phantasies and lends itself to rich and ever-varying expression ... which is capable of presenting various melodies simultaneously, grouping independent voices and producing dramatic effect with them; in a word, the only proper polyphonic auxiliary to the dramatic in music." While for all the great masters of the century, for Bach as for Handel, for Mozart as for Beethoven, the piano was the basis of musical education, the lever of their creative power, Gluck confined himself almost exclusively to vocal music and stringed instruments, a significant fact which explains the merits as well as defects in the master's later activity. The freedom and perfect ease with which the aforesaid musicians overcame the difficulties of counterpoint, we miss in Gluck's music, even at the time of maturity; and if it be urged that his musical plans for reform did not allow a development of the art of counterpoint, it may be remarked how little of it he showed in his church compositions. True, he has given us but one work of this kind, which appeared in Paris and later in Leipsic, a "De profundis" which seems, with its frequent but never quite complete examples of polyphony, a convincing proof that Gluck was not wholly familiar with polyphonic expression.