Beowulf can be considered an epic poem for a number of reasons, some of them outlined in the answer already given. Here are some additional reasons for considering Beowulf an epic:
- Epics often focus on single heroic figures (in this case, Beowulf).
- Epics often deal with war or with one-on-one combat, as in the three battles featured in this poem.
- Epics often involve heroic quests, as in Beowulf’s journey to Denmark.
- The hero of an epic poem often embodies the highest values of his culture.
- An epic poem is often “encyclopedic,” in the sense that the poem reflects an enormous number of different aspects of the culture from which it springs.
- An epic poem often contains, within itself, other genres of poetry, such as the lyric.
- Epic is often closely related to history as a genre.
- Epics often arise out of oral traditions in poetry, as is certainly the case with Beowulf.
- Epics often involve interactions between heroes and gods. In Beowulf, the Christian God is not immediately present in the poem but is often mentioned and discussed.
- Epic poems are often lofty in their styles of language, as is certainly the case with Beowulf.
- Epic poems often use so-called “epic formulas” – that is, phrases that are repeated and that are used in a variety of contexts.
- Epic often features a certain amount of boasting, as when Beowulf is provoked, by Unferth, into boasting about his exploits as a youth.
- Epic poems often feature tragic deaths, as in the tragic death of Beowulf himself.
For a fuller account of some of these features of epic, see the appropriate article in The Princeton Encyclopedia of Poetry and Poetics (Princeton: Princeton University Press, 1993.
When one discusses what makes Beowulf an epic, one is engaging in analysis of what literary critics call genre, a way of classifying literary works by similarities in style, theme, and other features. Traditional epic is a genre with roots in oral culture. The earliest epics (Gilgamesh, Iliad, Beowulf, etc.) are often considered paradigmatic of the genre. Typically, epics are long narrative poems recounting warlike and heroic actions, with the leading characters being kings, princes, or other important people. The emphasis of epic is normally on action rather than psychology. There is usually some sort of religious or divine or supernatural element in epics. Thus Beowulf displays many of the features typical of the epic genre, and is referred to as an epic.