The ancient Vikings and their descendants had great influence in European and even world history.
It is well known that they ruled over British territories for many years until finally being defeated by the Normans, which happen to be the descendants of Vikings that had received lands in Normandy (France).
In Italy, they founded the Norman kingdom of Sicily and even influenced many cultures thanks to their incursions in the Caliphate of Cordova and the Byzantine Empire.
Throughout the northern rivers, they intervened repeatedly in the Baltic Sea and in Russia, whose first states appear linked to Vikings adventurers.
The Viking history is a rich one, and while much is known about them, experts are still unable to understand as to why these Nordic warriors started to drastically expand, in search for lands to conquer or colonize from the VIII century onward.
The Vikings were great sailors and perhaps even better warriors, but what exactly made them such a powerful maritime culture has remained a mystery.
How did they navigate, and what tools did they use?
The Viking Solar Stones
For half a century, historians have wondered how the ancient Vikings sailed long distances under extremely difficult meteorological conditions.
Experts believe their secret were so-called Solar Stones, or Solar Crystals, intricate tools that allowed them to navigate across the oceans like no other culture before.
The conclusive evidence could be buried forever in the past, but a scientific study details the types of conditions under which ancient sailors could have used this tool, proving that it was possible for Vikings to navigate through the fog and other difficult conditions using little more than a polarized rock and a bit of mathematical knowledge.
The research was conducted by the Eötvös Loránd University in Hungary where scientists evaluated several types of polarizing glass under a variety of weather conditions throughout the year to test a hypothesis proposed in 1967.
According to Danish archaeologist Thorhild Ramskou, the Vikings were able to identify the position of the Sun through cloud cover by holding a birefringent material – such as crystallized calcium carbonate called Iceland Spar – to filter polarized light.
Sunlight passing through the translucent object could then be used in conjunction with a solar compass to calculate time and relative direction, which would aid in the determination of position on a map.
It was a convenient solution for the ancient sailors which allowed them to cross vast distances like no other culture before, reaching faraway lands like the American Continent, even before the arrival of Columbus.
In perfect conditions, the sun, stars, marine life and coastal features could be enough details needed for the Vikings to complete epic voyages.
However, the conditions around the frozen North Atlantic were not always ideal.
If undulating mist extensions do not make life inconvenient for the sailor, frequent cloud cover will indeed create problems.
That might have been less of a problem had they had magnetic compasses to help them get a sense of direction, but there is no evidence that the Vikings possessed such technology.
However, they did have something else. The Vikings had ‘Solar Stones’.
The so-called solar stones were mentioned in a number of ancient medieval scripts found across Europe.
While historical texts hint at their use in locating the Sun through thick cloud covers, they do not provide many details about exactly how they were used.
Thorhild Ramskou was the first modern scholar to suggest that these objects were crystals that could detect the precise location of the Sun based on its refraction of polarized light.
As light from the sun reaches the materials of the atmosphere, it disperses, making it almost impossible to tell the position of the Sun.
Luckily the orientation of the scattered light is slightly different to the light sun sliding through the clouds.
By rotating a polarizing filter in front of the eyes, it is possible to map the brightness of the sky and track the location of the Sun.
The birefringent materials divide the incoming light into two, resulting in a sort of double image.
The intensity of each image will vary depending on the angle and polarization of the light source.
It is not as simple as lifting a rock to unveil the Sun that hides behind the fog, requiring careful calibration and a keen eye.
The hypothesis has a lot of supporters, even if it’s a bit short on hard tests. No confirmed samples of ‘sunstones’ have been found, and only a single fragment of a potential Viking-age solar compass has emerged throughout the years.
To help complete some details about what is a highly speculative theory, Hungarian researchers tested three types of birefringent crystals under 1,080 variations of sun angle and degrees of cloud cover established under laboratory conditions in a planetarium.
Calcite, cordierite and tourmaline crystals were able to determine the angle of elevation of the Sun, especially at times near dawn and dusk. On average, experts found that calcite was the most accurate.
In short, if the Vikings used birefringent crystals at all, they would have found them more valuable when the Sun was relatively low in the sky near the summer solstice, and around the early morning at midnight, when it is obscured by low-level fog or cloud cover.
All of this may be considered far from being proof that the ancient Viking navigators used ‘Solar Crystals’ at all.
The data were also collected on solid ground within a room, not on the undulating seas.
However, nothing in the research discards the possibility, adding a degree of credibility to the hypothesis that the Vikings ruled the icy waves of the Atlantic with a sword in one hand and a gem in the other.
Featured image credit: Still from ‘Vikings’ TV show (History Channel)