Christoph Willibald Gluck was a composer of Italian and French opera in the early classical period. Born in the Upper Palatinate and raised in Bohemia, both part of the Holy Roman Empire, he gained prominence at the Habsburg court at Vienna. There he brought about the practical reform of opera's dramaturgical practices for which many intellectuals had been campaigning. With a series of radical new works in the 1760s, among them Orfeo ed Euridice and Alceste, he broke the stranglehold that Metastasian opera seria had enjoyed for much of the century. Gluck introduced more drama by using orchestral recitative and cutting the usually long da capo aria. His later operas have half the length of a typical baroque opera.

Opera is a form of theatre in which music is a fundamental component and dramatic roles are taken by singers. Such a "work" is typically a collaboration between a composer and a librettist and incorporates a number of the performing arts, such as acting, scenery, costume, and sometimes dance or ballet. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble, which since the early 19th century has been led by a conductor. Although musical theatre is closely related to opera, the two are considered to be distinct from one another.