Anglo-Saxon literature is filled with two common literary/poetic devices: kennings and alliteration. Alliteration is the repetition of a consonant sound within a line of poetry (used to elevate the language and the musical quality of the text). A kenning is a two or three word metaphorical phrase which elevates the language and makes for a more beautiful image. Both alliteration and kennings were used numerous times throughout Beowulf. 

A kenning used to describe the dragon is "fire-splitting terror." This kenning illustrates the dragon as a beast which bellows fire and is a frightening thing. A kenning used to describe Beowulf is "gray-bearded lord." This kenning illustrates that Beowulf is both a king and old.