In 19th-century Italian opera, la solita forma (literally conventional form or multipartite form or double aria) is the formal design of scenes found during the bel canto era of Rossini, Bellini, Donizetti up to the late operas of Verdi. The English phrase—"multipartite form"—is most often used by American musicologist Philip Gossett, beginning with a 1974 essay, where referring to a general framework of melodramatic scene types, especially duets. Each scene gradually progresses from an opening static lyric moment to a finale through several standard musical tempos and set pieces, gradually adding characters and adding or unraveling complexity in the plot.