Old English poetry falls broadly into two styles or fields of reference, the heroic Germanic and the Christian; these two are as often combined as separate in the poetry, which has survived for the most part in four major manuscripts.
The Anglo-Saxons left behind no poetic rules or explicit system; everything we know about the poetry of the period is based on modern analysis. The first widely accepted theory was constructed by Eduard Severs (1885). He distinguished five distinct alliterative patterns. The theory of John C. Pope (1942), which uses musical notation to track the verse patterns, has been accepted in some quarters, and is hotly debated.
The most popular and well-known understanding of Old English poetry continues to be Severs' alliterative verse. The system is based upon accent, alliteration, the quantity of vowels, and patterns of syllabic accentuation. It consists of five permutations on a base verse scheme; any one of the five types can be used in any verse. The system was inherited from and exists in one form or another in all of the older Germanic languages. Two poetic figures commonly found in Old English poetry are the kenning, an often formulaic phrase that describes one thing in terms of another (e.g. in Beowulf, the sea is called the whale road) and litotes, a dramatic understatement employed by the author for ironic effect.