Poetry in Literature

A poem is a composition written in verse (although verse has been equally used for epic and dramatic fiction). Poems rely heavily on imagery, precise word choice, and metaphor; they may take the form of measures consisting of patterns of stresses (metric feet) or of patterns of different-length syllables (as in classical prosody); and they may or may not utilize rhyme. One cannot readily characterize poetry precisely. Typically though, poetry as a form of literature makes some significant use of the formal properties of the words it uses – the properties of the written or spoken form of the words, independent of their meaning. Meter depends on syllables and on rhythms of speech; rhyme and alliteration depend on the sounds of words.
Arguably, poetry pre-dates other forms of literature. Early examples include the Sumerian Epic of Gilgamesh (dated from around 2700 B.C.), parts of the Bible, the surviving works of Homer (the Iliad and the Odyssey), and the Indian epics Ramayana and Mahabharata. In cultures based primarily on oral traditions the formal characteristics of poetry often have a mnemonic function, and important texts: legal, genealogical or moral, for example, may appear first in verse form.
Some poetry uses specific forms. Examples include the haiku, the limerick, and the sonnet. A traditional haiku written in Japanese relate to nature, contain seventeen onji (syllables), distributed over three lines in groups of five, seven, and five, and should also have a kigo, a specific word indicating a season. A limerick has five lines, with a rhyme scheme of AABBA, and line lengths of 3,3,2,2,3 stressed syllables. It traditionally has a less reverent attitude towards nature. Poetry not adhering to a formal poetic structure is called "free verse".
Language and tradition dictate some poetic norms: Persian poetry always rhymes, Greek poetry rarely rhymes, Italian or French poetry often does, English and German poetry can go either way. Perhaps the most paradigmatic style of English poetry, blank verse, as exemplified in works by Shakespeare and Milton, consists of unrhymed iambic pentameters. Some languages prefer longer lines; some shorter ones. Some of these conventions result from the ease of fitting a specific language's vocabulary and grammar into certain structures, rather than into others; for example, some languages contain more rhyming words than others, or typically have longer words. Other structural conventions come about as the result of historical accidents, where many speakers of a language associate good poetry with a verse form preferred by a particular skilled or popular poet.
Works for theatre (see below) traditionally took verse form. This has now become rare outside opera and musicals, although many would argue that the language of drama remains intrinsically poetic.
In recent years, digital poetry has arisen that takes advantage of the artistic, publishing, and synthetic qualities of digital media.