How did Alessandro Scarlatti shape the Italian opera overture?

Alessandro Scarlatti played a pivotal role in the evolution of the overture by formalizing the Italian opera overture, known as the sinfonia avanti l’opera.12

He established a standard three-section structure consisting of a fast-slow-fast (allegro-adagio-allegro) sequence. This format departed from the more contrapuntal French overture style, favoring a tuneful, predominantly homophonic texture that became a foundational model for the early symphony.132

Scarlatti’s contributions to this form included:
* Structural Formalization: By standardizing the three-movement design, he provided a blueprint for the earliest symphonies.132
* Orchestral Development: He moved away from using strings primarily for introductions and ritornelli, placing greater emphasis on orchestral accompaniment for voices and introducing wind instruments like trumpets, flutes, oboes, bassoons, and horns for specific effects.1
* Melodic Clarity: His work emphasized clear, symmetrical phrasing and chordal textures, which contrasted with the complex counterpoint of the earlier Baroque era and prefigured the attitudes of later Classical composers.2