The term "heroic couplet" is sometimes reserved for couplets that are largely closed and self-contained, as opposed to the enjambed couplets of poets like John Donne. The greatest masters of the heroic couplet in English, thus defined, are generally considered to be John Dryden and Alexander Pope. Major poems in the closed couplet, apart from the works of Dryden and Pope, are Samuel Johnson's The Vanity of Human Wishes, Oliver Goldsmith's The Deserted Village, and John Keats's Lamia. The form was immensely popular in the 18th century. The looser type of couplet, with occasional enjambment, was one of the standard verse forms in medieval narrative poetry, largely because of the influence of the Canterbury Tales.
English heroic couplets, especially in Dryden and his followers, are sometimes varied by the use of the occasional alexandrine, or hexameter line, and triplet. Often these two variations are used together to heighten a climax. The breaking of the regular pattern of rhyming pentameter pairs brings about a sense of poetic closure. Here are three examples from Book IV of Dryden's translation of the Aeneid.
Alexandrine and Triplet
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Jun 04, 2006; According to Timothy Mowl, the early 18th century was a pretty dismal time: an era of artistic impoverishment and cultural stasis...