The Viking Sunstone: Medieval Ingenuity and Maritime Navigation

Unexplained Mysteries

The Viking reputation has grown immensely in recent decades. Long-held characterizations of these Norse warriors as hairy, violent and straightforward is being overthrown, replaced by a picture of a sophisticated and nuanced people.

Most of these prejudices come from the victims of Norse raids, it is true, and so can be excused a certain degree of authorial bias. When all you know of a people is that they occasionally turn up at your doorstep and kill everyone, you can be expected to form a view based only on that.

But we now know with a fair certainty that Vikings crossed the Atlantic centuries before Columbus. These were not just opportunistic mobs, these were skilled sailors and navigators.

And how did they manage this, so far before everyone else? Maybe they used a sunstone.

Natural Navigation

In fact, we know they did use a sunstone. Several Icelandic texts from the Middle Ages attest to the use of a sunstone to navigate both overland and on the sea due to its unique property of being ab le to find the sun, even in an overcast sky.

This is important in Scandinavia, given that overcast skies happen frequently. Being able to locate the sun means being able to orient yourselves in the landscape, something not so easily done in a blank daytime sky.

Also, and amazingly, we even know what a sunstone is. Several naturally occurring minerals found in Europe, most notably Iceland spar (a colorless crystalline material) have polarizing properties which occur whether the sky is clear or cloudy, and therefore allow the user to orient themselves to face the sun, even if they cannot see it.

Obviously this is extremely useful as a tool for navigation which works entirely independently of other landmarks. This would make it ideal for maritime navigation.

Equally obviously there are several sizeable limitations to the effectiveness of the sunstone. Most obviously, it doesn’t work at night, and doubtless the much preferred celestial navigation would offer a better alternative.

But it remains as an interesting curiosity of the Viking era, a medieval observation put to practical use and a useful device for finding your way around unfamiliar territory. Or does it?

You see, we don’t actually know if sunstones were even real. They are attested in various Icelandic sources, to be sure, but these sources themselves are problematic.

Hrafns saga Sveinbjarnarsonar, and Rauðúlfs þáttr the major sources which discuss sunstones, are entirely allegorical. The first involves visions of celestial knights and the second is entirely a parable about Saint Olav. Neither is intended to be taken literally.

So if nothing else in these texts is literally true, then should the sunstone be seen as allegorical as well? There are certainly later medieval texts which, drawing on these sagas, certainly believe the sunstone was real.

And there is Icelandic spar, which does everything a sunstone is supposed to and which would be highly improbable as a coincidental solution. Maybe at the heart of these allegories, something magical turned out to be real after all.

Top Image: An understanding of Viking technology and Icelandic geology has allowed us to piece together what a sunstone likely was. Source: Pam Walker / Adobe Stock.

By Joseph Green

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Joseph Green is editor for Historic Mysteries, which combines his background in English Literature with a lifelong fascination for the strange and the unexplained.

References

• Skjalden, 2021. Viking Sunstone – Iceland Spar. Available at: https://skjalden.com/viking-sunstone/

• Banguet, L, 2011. Viking ‘sunstone’ more than a myth. Available at: https://phys.org/news/2011-11-viking-sunstone-myth.html

• Milligan, M, 2022. Sunstones – The Viking Navigation Crystals. Available at: https://www.heritagedaily.com/2022/07/sunstones-the-viking-navigation-crystals/144085