The rules made by the singers and in force in Handel's time did not stop at the distribution of the voices. They prescribed also the kinds and number of arias, duets, etc. There were five kinds of aria: _aria cantabile_, _aria di portamento_, _aria di mezzo carattere_, _aria parlante_, _and aria di bravura_. _Aria cantabile_ was slow and flowing and usually pathetic in style. _Aria di portamento_ was also slow, but with stronger rhythm and wider intervals. _Aria parlante_ was declamatory. _Aria di mezzo carattere_ was an air of medium character, containing a fusion of styles. _Aria di bravura_ was one in which every possible opportunity was given the singer for a display of agility in the way of runs, trills, jumps, _et cætera_. The rules also commanded that every scene in an opera should end with an aria, and that in each act every principal singer should have one aria. No singer could have two arias in succession, nor in any circumstances might two arias of the same kind stand together. The hero and heroine had each to have one _aria di bravura_ and one duet. The opera ended with a dance and chorus. At one time no trios, quartets, or concerted pieces were allowed. A natural result of such rules was that opera librettos were very poor stuff generally, and had little dramatic sense or force. Composers often took a lot of good airs and duets from operas which had failed, and strung them together with new text to make a new opera. It was an experiment of this kind which led Gluck, as we shall see, to doubt the possibility of producing anything artistic according to the extant methods of Italian opera. As Gluck's movement of reform was undertaken in Paris, and as his works lie rather in the line of development of French opera than of Italian, I shall recount the story of his battle in the narrative of the growth of the French school. It is sufficient for the present to say that his labors had no very serious influence on Italian composers. They continued to write tune for tune's sake, and their modifications in style and form would have come about without the intervention of Gluck. Immediately after Handel the Neapolitan school of composers was conspicuous through its development of opera buffa, comic grand opera. The principal writers were Logroscino, Leo, Hasse, and Pergolesi. The last was popular both as a serious and a comic writer somewhat later than 1770. Later still came forward Sacchini, Galuppi, Paisiello and Piccini. The last named, a contemporary of Gluck and Mozart, and Gluck's opponent in Paris, was a most melodious writer. He deserves special mention for his development of the operatic finale. His finales were long concerted pieces in which the various voices were united in rich harmonies so as to produce a strong effect. Chapter XX Italian Opera to Verdi