Term denoting type of Eng. Restoration drama in which there were extensive mus. episodes, similar to masques, perf. only by subsidiary characters. Form was developed by Betterton with The Tempest, 1674, an adaptation of Shakespeare's play with mus. by Humfrey, Locke, and others. Another example was King Arthur, text by Dryden (1684) and mus. by Purcell (1691). Purcell was also involved in Dioclesian (1690), The Fairy Queen (1692, rev. 1693), and The Indian Queen (1695). Only King Arthur was specifically devised as a semi‐opera, the others being Betterton versions of earlier plays. Daniel Purcell, John Eccles, and D'Urfey also wrote semi‐operas, but early in the 18th cent. the form was superseded by It. opera.