- longed and intricate figures or 'roulades' to single syllables, every sort of
embellishment, like grace-notes, trills and turns, and rapid variations or contrasts of register, with tones at the extremes of the vocal compass. The 'aria parlante' might also pass over under certain dramatic conditions into the 'aria strepitosa' or 'aria infuriata,' in which the acme of agitation or of violent passion was expressed. So urgent was the demand for all these types as exhibitions of vocal dexterity that it became the rule that in each main division of an opera there should be at least one example of each of the principal classes, and also that no two successive arias should come from the same class. The principal singers in the cast acquired the right to have opportunity to parade themselves in all the more difficult and showy forms, especially in the final portion of the work, and usually the climax of interest included a grand duet between the leading characters. All these conventional usages arose from the popular conception of the musical drama as a grand concert-entertainment rather than a drama pure and simple.
The use of the orchestra also tended to become stereotyped. At the opening of a work was usually an overture of varied dimensions. Sometimes it was a mere tonal introduction in but one movement, but in larger works it consisted of three to four movements, each of a distinct character. Two main types of overture were distinguished, the French, which originated with Lully, having a first movement in full harmony, stately and even grandiose, the second in quick tempo, more or less fugal and with more distinction of instruments, the third a flowing melody in moderate tempo, and the fourth, if present, a dance like a gavotte or minuet; and the Italian, which was first established by Scarlatti, having a first movement in quick and incisive style, a second like the third above, and a third again quick and often contrapuntal. The relation of the overture to the topic and spirit of the work as a whole was so slight that overtures were often transferred from work to work, and even from operas to oratorios. Besides the overture, opportunities were seized to introduce instrumental numbers into the progress of the action, such as marches, dances, pictorial scenes—anything to enhance the tonal variety and interest. Accompaniments were more and more made a special study, particularly as the capacities of the orchestra became better understood. Yet they were strictly accompaniments, designed to support and set off the voice, rather than to supply an independent development of the dramatic situation in any large way. The harpsichord remained the basis or centre for the whole ensemble, filling in all harmonic gaps and often serving alone.
The general plan of disposing the dramatic and musical resources
involved properly three or four male and three female
characters, the hero or 'primo uomo' being a high tenor and
the heroine or 'prima donna' a soprano—the latter until well
on into the 18th century being an artificial male soprano, since
the opposition to women-singers on the stage was outgrown only
