In Norse mythology, Gjallarhorn (Old Norse "yelling horn" or "the loud sounding horn") is a mystical horn blown at the onset of Ragnarök associated with the god Heimdallr and the wise being Mímir. Gjallarhorn is attested in the Poetic Edda, compiled in the 13th century from earlier traditional material, and the Prose Edda, written in the 13th century by Snorri Sturluson.
Poetic Edda 
The single mention of Gjallarhorn by name occurs in the Poetic Edda poem Völuspá, wherein a völva foresees the events of Ragnarök and the role in which Heimdallr and Gjallarhorn will play at its onset; Heimdallr will raise his horn and blow loudly. Due to manuscript differences, translations of the stanza vary:
Benjamin Thorpe translation:
Henry Adams Bellows translation:
Regarding this stanza, scholar Andy Orchard comments that the name Gjallarhorn may here mean "horn of the river Gjöll" as "Gjöll is the name of one of the rivers of the Underworld, whence much wisdom is held to derive", but notes that in the poem Grímnismál, Heimdallr is said to drink fine mead in his heavenly home Himinbjörg.
Earlier in the same poem, the völva mentions a scenario involving the hearing or horn (depending on translation of the Old Norse noun hljóð—bolded below for the purpose of illustration) of the god Heimdallr:
- Henry Adams Bellows translation:
- I know of the horn of Heimdall, hidden
- Under the high-reaching holy tree;
- On it there pours from Valfather's pledge
- A mighty stream: would you know yet more?
- Carolyne Larrington translation:
- She knows that Heimdall's hearing is hidden
- under the radiant, sacred tree;
- she sees, pouring down, the muddy torrent
- from the wager of Father of the Slain; do you
- understand yet, or what more?
Scholar Paul Schach comments that the stanzas in this section of Voluspa are "all very mysterious and obscure, as it was perhaps meant to be". Schach details that "Heimdallar hljóð has aroused much speculation. Snorri seems to have confused this word with gjallarhorn, but there is otherwise no attestation of the use of hljóð in the sense of 'horn' in Icelandic. Various scholars have read this as "hearing" rather than "horn".
Scholar Carolyne Larrington comments that if "hearing" rather than "horn" is understood to appear in this stanza, the stanza indicates that Heimdall, like Odin, has left a body part in the well; his ear. Larrington says that "Odin exchanged one of his eyes for wisdom from Mimir, guardian of the well, while Heimdall seems to have forfeited his ear."
Prose Edda 
In the Prose Edda, Gjallarhorn is mentioned thrice, and all three mentions occur in Gylfaginning. In chapter 14, the enthroned figure Just-As-High tells the disguised Gangleri about the cosmological tree Yggdrasil. Just-As-High says that one of the three roots of Yggdrasil reaches to the well Mímisbrunnr, which belongs to Mímir, and contains much wisdom and intelligence. Using Gjallarhorn, Heimdallr drinks from the well and thus is himself wise.
In chapter 25 of Gylfaginning, High tells Gangleri about Heimdallr. High mentions that Heimdallr is the owner of the "trumpet" (see footnote) Gjallarhorn and that "its blast can be heard in all worlds". In chapter 51, High foretells the events of Ragnarök. After the enemies of the gods will gather at the plain Vígríðr, Heimdallr will stand and mightily blow into Gjallarhorn. The gods will awake and assemble together at the thing.
Archaeological record 
A figure holding a large horn to his lips and clasping a sword on his hip appears on a stone cross from the Isle of Man. Some scholars have theorized that this figure is a depiction of Heimdallr with Gjallarhorn.
A 9th or 10th century Gosforth Cross in Cumbria, England depicts a figure holding a horn and a sword standing defiantly before two open-mouthed beasts. This figure has been oft theorized as depicting Heimdallr with Gjallarhorn.
Theories and interpretations 
Scholar Rudolf Simek comments that the use of a horn as both a musical instrument and a drinking vessel is not particularly odd, and that the concept is also employed with tales of the legendary Old French hero Roland's horn, Olifant. Simek notes that the horn is among the most ancient of Germanic musical instruments, along with lurs, and, citing archaeological finds (such as the 5th century Golden Horns of Gallehus from Denmark), comments that there appears to have been sacral horns kept purely for religious purposes among the Germanic peoples, understood as earthly versions of Heimdallr's Gjallarhorn, reaching back to the early Germanic Iron Age.
In popular culture 
Since 2007, a Gjallarhorn has been used to announce the arrival of the Minnesota Vikings on the field at their home games. The honor of sounding this Gjallarhorn is traditionally given to famous Minnesota athletes and other state celebrities.
See also 
- The Snoldelev Stone, a 9th century runestone featuring a unique three-horned symbol
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- Orchard (1997:57).
- Simek (2007:110).
- Thorpe (1866:9).
- Bellows (1923:20). See connected footnote for information on manuscript and editing variations.
- Thorpe (1866:7).
- Bellows (1932:12).
- Larrington (1999:7).
- Schach (1985:93).
- Larrington (1999:265).
- Faulkes (1995:17).
- Faulkes (1995:25). Lindow (2002:143) comments that the Old Norse term employed for the instrument refers to "a long brass instrument that would answer today to an unvalved trumpet".
- Faulkes (1995:54).
- Lindow (2002:168).
- Bailey (1996:86-90).
- Simek (2007:110—111).
- Bellows, Henry Adams (1923). The Poetic Edda. American-Scandinavian Foundation.
- Faulkes, Anthony (Trans.) (1995). Edda. Everyman. ISBN 0-460-87616-3
- Bailey, Richard N. (1996). England's Earliest Sculptors. University of Toronto. ISBN 0-88844-905-4.
- Larrington, Carolyne (Trans.) (1999). The Poetic Edda. Oxford University Press. ISBN 0-19-283946-2
- Lindow, John (2002). Norse Mythology: A Guide to the Gods, Heroes, Rituals, and Beliefs. Oxford University Press. ISBN 0-19-515382-0
- Orchard, Andy (1997). Dictionary of Norse Myth and Legend. Cassell. ISBN 0-304-34520-2
- Thorpe, Benjamin (Trans.) (1866) The Elder Edda of Saemund Sigfusson. Norrœna Society.
- Schach, Paul (1985). "Some Thoughts on Völuspá" as collected in Glendinning, R. J. Bessason, Heraldur (Editors). Edda: a Collection of Essays. University of Manitoba Press. ISBN 0-88755-616-7
- Simek, Rudolf (2007) translated by Angela Hall. Dictionary of Northern Mythology. D.S. Brewer ISBN 0-85991-513-1