of aria came gradually to be associated with the ritornello (literally, 'little return'), a recurring instrumental episode which was interspersed with the elements of the aria and eventually provided, in early operas, the opportunity for dancing or entries of characters. This version of aria form with ritornelli became a dominant feature of European opera throughout the 18th century. It is thought by some writers to be the origin of the instrumental forms of concerto and sonata form. The ritornelli became essential to the structure of the aria – "while the words determine the character of a melody the ritornello instruments often decided in what terms it shall be presented." 18th century By the early 18th century, composers such as Alessandro Scarlatti had established the aria form, and especially its da capo version with ritornelli, as the key element of opera seria. "It offered balance and continuity, and yet gave scope for contrast. [...] The very regularity of its conventional features enabled deviations from the normal to be exploited with telling effect." In the early years of the century, arias in the Italian style began to take over in French opera, giving rise eventually to the French genre of ariette, normally in a relatively simple ternary form. Types of operatic aria became known by a variety of terms according to their character – e.g.aria parlante ('speaking-style', narrative in nature), aria di bravura (typically given to a heroine), aria buffa (aria of a comic type, typically given to a bass or bass-baritone), and so on. M. F. Robinson describes the standard aria in opera seria in the period 1720 to 1760 as follows: The first section normally began with an orchestral ritornello after which the singer entered and sang the words of the first stanza in their entirety. By the end of this first vocal paragraph the music, if it were in a major key as it usually was, had modulated to the dominant. The orchestra then played a second ritornello usually shorter than the first. The singer re-entered and sang the same words through a second time. The music of this second paragraph was often slightly more elaborate than that of the first. There were more repeats of words and perhaps more florid vocalisations. The key worked its way back to the tonic for the final vocal cadence after which the orchestra rounded the section off with a final ritornello. The