“’Mongst shivering giants wider known
Than him who sits unmoved on high,
The guard of heaven, with sleepless eye.”
Lay of Skirner (Herbert’s tr.).
Heimdall was provided further with a flashing sword and a marvellous trumpet, called Giallar-horn, which the gods bade him blow whenever he saw their enemies approach, declaring that its sound would rouse all creatures in heaven, earth, and Nifl-heim. Its last dread blast would announce the arrival of that day when the final battle would be fought.
“To battle the gods are called
By the ancient
Gjallar-horn.
Loud blows Heimdall,
His sound is in the air.”