An animal epithet is a name used to label a person or group, by association with some perceived quality of an animal. Epithets may be formulated as similes, explicitly comparing people with the named animal, or as metaphors, directly naming people as animals. Animal epithets may be pejorative, readily giving offence, but they are also used in political campaigns. One English epithet, lamb, is always used positively. Animal similes and metaphors have been used since classical times, for example by Homer and Virgil, to heighten effects in literature, and to sum up complex concepts concisely.