“In prosody, unrhymed verse. In English, the term usually means unrhymed iambic pentameter. In classical prosody, rhyme was not used at all; with the introduction of rhyme in the Middle Ages, blank verse disappeared. It was reintroduced in the 16th century and in England became the standard medium of dramatic poetry and frequently of epic poetry. Shakespeare’s plays, for example, are written mostly in blank verse.”
Excerpted from: Murphy, Bruce, ed. Benet’s Reader’s Encyclopedia, Fourth Edition. New York: Harper Collins, 1996.