What language was the Old English epic poem "Beowulf" written in?

The Old English epic poem Beowulf was written in Old English, the language used in England before the Norman Conquest transformed English vocabulary and literary culture. More precisely, the surviving text is predominantly in the Late West Saxon dialect, although it preserves forms associated with several Old English dialect regions.

Beowulf contains 3,182 alliterative lines and survives in the Nowell Codex, a manuscript copied around the late 10th or early 11th century. Its anonymous poet tells of Beowulf, a hero of the Geats, who fights Grendel, Grendel’s mother, and, decades later, a dragon. The action is set mainly in a legendary Scandinavian world.

Old English can look almost unrecognizable to modern English readers. Its grammar, vocabulary, and pronunciation differ substantially from today’s language; “Hwæt,” the poem’s famous opening word, has been translated in several ways, including “Listen,” “Lo,” and “So.” The poem’s language is sometimes called Anglo-Saxon, though Old English is the standard linguistic name. The date of composition and the identity of its author remain debated.