Bifröst is the bridge between the realm of humans, Midgard, and the realm of the gods, Asgard, in the cosmology of the pre-Christian Germanic peoples. It’s most famously associated with rainbows, and has been called the Rainbow Bridge; most times you’ve seen the term “Rainbow Road” it’s a reference to Bifröst as well. Rainbows are used as symbols in today’s world, to represent LGBTQIA groups, and also as a banner for any cause trying to unite diverse viewpoints, cultures, or nations. Can we learn anything from the association of rainbows with the ancient Germanic bridge to the gods?
First, one of the more important attestations of Bifröst in the literature, from Gylfaginning 13:
Then said Gangleri: “What is the way to heaven from earth?” Then Hárr answered, and laughed aloud: “Now, that is not wisely asked; has it not been told thee, that the gods made a bridge from earth, to heaven, called Bifröst? Thou must have seen it; it may be that ye call it rainbow.’ It is of three colors, and very strong, and made with cunning and with more magic art than other works of craftsmanship. But strong as it is, yet must it be broken, when the sons of Múspell shall go forth harrying and ride it, and swim their horses over great rivers; thus they shall proceed.” Then said Gangleri: “To my thinking the gods did not build the bridge honestly, seeing that it could be broken, and they able to make it as they would.” Then Hárr replied: “The gods are not deserving of reproof because of this work of skill: a good bridge is Bifröst, but nothing in this world is of such nature that it may be relied on when the sons of Múspell go a-harrying.”
“Gangleri” is a pseudonym of Gylfi, a mythological first king of Sweden; “Hárr,” or High, is Odin, exchanging knowledge with Gylfi as with many of the poems of the elder Edda. Later on in Gylfaginning, Bifrost is described as the best of bridges; the red colors in the bridge are described as a kind of fire; and the upper end of the bridge is noted to be rooted in Himinbjörg, home of Heimdall who stands guard over the bridge until it must fall at Ragnarok. One important daily use of Bifrost is mentioned in chapter 15: “The third root of the Ash stands in heaven; and under that root is the well which is very holy, that is called the Well of Urdr; there the gods hold their tribunal. Each day the Æsir ride thither up over Bifröst, which is also called the Æsir’s Bridge (Ásbrú).”
Gylfaginning was written in the 13th Century by a Christian scholar; there are some attestations going back farther in the poems of the elder Edda. The mention in Grimnismal is the source of Snorri’s description of Bifrost as the best of bridges. The other mention is in Fafnismal, one of several sources for the battle between Sigurd and the dragon Fafnir. This description mentions Ragnarok as well:
14. “Tell me then, Fafnir, | for wise thou art famed,
And much thou knowest now:
How call they the isle | where all the gods
And Surt shall sword-sweat mingle?”
15. “Oskopnir is it, | where all the gods
Shall seek the play of swords;
Bilrost breaks | when they cross the bridge,
And the steeds shall swim in the flood
Of course, here we see that Snorri Sturluson, the scholar who tried to use the old myths to make a textbook in the Thirteenth Century, is actually using a slightly different word than what we’ve found in the written sources for the original Eddic poems. Snorri calls the bridge Bifröst; the older sources used the term Bilröst. What’s the difference?
According to scholar John Lindow, Bilröst comes from two roots: Bil which means “stopping place, time, instant, weak spot,” and röst, which means “league” or “current,” in this context meaning something like “road” or “path”. Rudolf Simek interprets this as “fleetingly glimpsed rainbow”; while I’m not an expert in Old Norse, I see something more like an ephemeral path, since Snorri is explicitly calling the rainbow an alternative name. The “weak spot” is interesting, too, given Bifrost’s prophesied role in Ragnarok.
The now widely-accepted root Bif, however, means “quavering” or “shaking”, which lines up with the fleeting nature of rainbows, the riding of the Aesir over the bridge every day, and the destruction of the bridge at Ragnarok. It’s a good term to continue to use for the bridge constructed to allow the gods to visit the realm of humans, whether that was the term used by the ancient Germanic peoples or not. Though the pronunciation used in the Thor films is wrong – it’s not “by frost”, it’s “beef roast” or “beef rost”. Given the two parts of the word, the “f” (or the “l”) has to go with the first syllable of the pronunciation.
Bifrost isn’t just interesting etymologically, though. It is one of the few items mentioned in the mythological literature that is at any point grounded to real-world phenomena. I am often skeptical of Snorri’s scholarship, since he was working over 200 years after Iceland converted and his intention was not to preserve the ancient myths; in fact, much of his Prose Edda is explicitly explaining the myths as Christian in origin and redefining the Germanic gods as human kings and queens. However, the fact that he mentions Bifrost as being synonymous with rainbows while the earlier poems do not is not necessarily indicative of error or poetic license. Snorri likely had access to sources we do not, and the actual oral tradition of these myths definitely had more cultural sway at that time. Some scholars have tried to assign the Bifrost to other real-world phenomena, the Milky Way most prominently. I’m more convinced that the Milky Way was assigned to another part of the Germanic cosmos, at least in those lands farther north: the world tree Yggdrasil. Other people have tried to imagine the Aurora Borealis as a kind of Bifrost, but they’re pretty obviously wrong, too. Snorri got this one right. Rainbows are the pathway to the gods.
So in the end, what can we say of how the pre-Christian Germanic peoples conceptualized rainbows; that is, what did they think and feel when they saw a rainbow appear in the sky? As much as we can say anything about long-dead ancestors, it seems likely that when the Vikings and their forebears and other followers of the Aesir saw rainbows, they were comforted by this reminder that the gods were always present as a part of their world, participating as real animating forces in the ongoing cycle of birth, life, death, and rebirth. Some may have been awed by rainbows, by their association with rain (and therefore Thor) and the fiery colors of the rainbow; some may have reflected on loved ones carried off by the Valkyries to Valhalla, or taken over another famous bridge Gjallarbrú to reside with most of the dead in Hel. Undoubtedly some were reminded of the fated end of Bifröst at Ragnarok.
Fundamental to the worldview of these peoples was accepting that death came for us all, but that we live on as part of the cycle of life, in an afterlife perhaps, but more literally as parents, elders, ancestors, and even as part of the soil. Rainbows, and their connection to the gods, to Asgard and Yggdrasil, are every bit a part of that worldview, too.