The narrator uses a common historical idiom, the “vault of heaven,” when praising the bravery of Beowulf and his band of warriors. After Beowulf mortally injures Grendel, the monster flees back to its lair. After surveying Grendel’s lair and confirming that he has died, the band of warriors returns to Heorot:
Home then rode the hoary clansmen
from that merry journey, and many a youth,
on horses white, the hardy warriors,
back from the mere. Then Beowulf's glory
eager they echoed, and all averred
that from sea to sea, or south or north,
there was no other in earth's domain,
under vault of heaven, more valiant found,
of warriors none more worthy to rule!
Beowulf earns the praise and admiration of those around him for his incredible accomplishment in defeating the supernaturally strong Grendel. “Beowulf’s glory” is “echoed” by all, and the group declares that there is no warrior “more valiant” than him anywhere on earth, from “sea to sea, or north to south,” neither on Earth nor “under vault of heaven.” The “vault of heaven” is a historical idiom that metaphorically imagines the stars and planets as if they were painted on the ceiling of some tremendous building, such as a church. Many ancient cultures believed that the earth was flat and that the stars and planets were embedded in a spherical dome or “vault” over the earth, and the poem’s use of this idiom both reflects this once-common belief and emphasizes Beowulf's achievement.