But the very fertility of his invention and the ease and rapidity with which his musical thoughts flowed from his pen generated a tendency toward the adoption of a stereotyped style, influenced as he was by the growing inclination of his pleasure-loving Neapolitan audiences to demand triviality more than dramatic seriousness, tuneful melody and vocal display more than sincerity of expression. He did not possess the rugged tenacity of artistic purpose that drove Gluck, a half-century later, to insist on the primacy of the dramatic intent and the complete subordination of the musical element to the dramatic. So we find that under his hand the cantata, as well as the opera, became conventionalized in form. The vocal element, on which he lavished greatest care, became predominant and the aria, as the chief means of vocal utterance, fell under the same spell of conventionality. But in the cantatas, especially in the essentially musical parts, there are comparatively few evidences of the spirit of triviality that he so freely admitted into his operas. It is not true, as is frequently asserted, that Scarlatti invented the stereotyped forms of the aria that were the chief stock in trade of his successors in Italian opera until the middle of the nineteenth century. Nearly all of these aria-forms, including the commonest and most banal operatic form, the one with the indispensable _da capo_, may be found in the cantatas and operas of the composers already mentioned, among whom the inclination toward definite organization in melodic form was already well developed before Scarlatti had more than begun his career as composer. The incredible number of arias that he wrote and their easy classification as to form certainly made this common error of statement a very pardonable one. From his position as the greatest composer of his period, however, he gave to their use an authority and an impetus whose force was not fully spent for a century and a quarter after his death. But if Scarlatti’s contributions to the cantata and opera were mainly along the line of the glorification of the purely musical and vocal elements, in one direction certainly he contributed richly to the permanent progress of musical art. In Carissimi’s cantatas the accompaniments were very simple, written usually with figured bass only, which was left to the performers to fill in at their discretion. After Carissimi the accompaniment began to assume a more elaborate character, but many of Scarlatti’s show utmost care in working out. Most of these were for violin or ‘cello. Some of those for ‘cello required such large technical equipment that ability to play them was looked upon as a mark of distinguished musicianship. Indeed, it was not uncommon in that age, which was far more superstitious than our own, for audiences, deeply impressed with the beauty of tone and marvellous skill of the performers, to believe and declare that angels had assumed the form of men.