The masque was a form of entertainment which flourished in late 16th and early 17th century England, though developed earlier in Italy. It involved dancing, acting, music and usually elaborate stage design. It was usually performed by amateurs.
The masque has its origins in a folk tradition where masked players would unexpectedly call on noblemen's houses danicng and bringing gifts on certain nights of the year. Spectators were invited to join in the dancing. At the end, the players would take off their masks to reveal their identities.
Later, in the court of James I of England, narrative elements of the masque became more significant. Plots were often on classical or allegorical themes, and were usually acted out by amateurs. At the end, the audience would join in a final dance. Ben Jonson wrote a number of masques with stage design by Inigo Jones. Their works are usually thought of as the most significant in the form. Sir Philip Sidney also wrote masques.
Shakespeare wrote a masque-like interlude in The Tempest. There is also a masque sequence in his Henry VIII. John Milton's Comus (with music by Henry Lawes) is described as a masque, though is generally reckoned as a pastoral play.
The part-opera which developed in the latter part of the 17th century and in which form John Dryden and Henry Purcell collaborated, is somewhat related to the masque. In the 20th century, Ralph Vaughan Williams wrote Job: A Masque for Dancing, although the work is closer to a ballet than a masque as it was originally understood. His designating it a masque was to indicate that choreography typical when he wrote the piece would not be suitable.
Constant Lambert also wrote a piece he called a masque, Summers Last Will and Testament.
The word masque is sometimes also used to mean a masquerade ball.