The Beowulf manuscript was copied around 1000 AD, preserving what is generally accepted as the greatest Old English poem, which narrates the heroic deeds of a Geatish warrior against monsters threatening the Danish king's great hall of Heorot. Though Heorot is a hall rather than a castle in the later sense, it functions as a fortified communal space whose integrity is threatened by forces of darkness and chaos from without. The poem is the earliest major poem in the English literary tradition and the first in which a defended built space plays a central role.

Beowulf established in English poetry the archetype of the hall or fortress as a site of communal civilisation threatened by external darkness — a structure that recurs in castle poetry from the medieval period through Tolkien. Tolkien's celebrated 1936 lecture on Beowulf and his own legendarium drew directly on the poem's imagery of embattled hall and howling wilderness. Seamus Heaney's 1999 translation opened Beowulf to a new generation of readers and was widely celebrated as a landmark in modern poetry.