that a new, more elevated form of opera was necessary. Their ideas would give birth to a genre, opera seria (literally "serious opera"), which would become dominant in Italy and much of the rest of Europe until the late 18th century. The influence of this new attitude can be seen in the works of the composers Carlo Francesco Pollarolo and the enormously prolific Alessandro Scarlatti. During the 18th century artistic and cultural life in Italy was heavily influenced by the aesthetic and poetic ideals of the members of the Accademia dell'Arcadia. The Arcadian poets introduced many changes to serious music drama in Italian, including: the simplification of the plot; the removal of comic elements; the reduction of the number of arias; a predilection for plots drawn from ancient Classical or modern French tragedy, in which the values of loyalty, friendship and virtue were extolled and the absolute power of the sovereign was celebrated. By far the most successful librettist of the era was Pietro Metastasio and he maintained his prestige well into the 19th century. He belonged to the Arcadian Academy and was firmly in line with its theories. A libretto by Metastasio was often set by twenty or thirty different composers and audiences came to know the words of his dramas by heart. Opera buffa In the 17th century comic operas were produced only occasionally and no stable tradition was established. Only in the early years of the 18th century was the comic genre of opera buffa born in Naples and it began to spread throughout Italy after 1730. Opera buffa was distinguished from opera seria by numerous characteristics: the importance given to stage action and the consequent need for the music to follow the changes of the drama, emphasising the expressiveness of the words; the choice of singers who were also excellent actors able to perform the drama convincingly; a reduction in the use of scenery and stage machinery and in the number of orchestral players; the use of a small cast of characters (at least in the short form of comic opera known as the intermezzo) and simple plots (a good example being Pergolesi's La serva padrona, 1733); libretti inspired by commedia dell'arte, with realistic subjects, colloquial language and slang expressions; as far as singing was concerned: the complete rejection of vocal virtuosity; a tendency to an incorrect pronunciation of the words; the frequent presence of rhythmic