Tag Archives: tar

Vikings conquered Europe thanks to a technological innovation: tar

While the Vikings had plenty of assets going for them, a surprising advancement gave them a bit of an edge over other seafaring peoples: tar. They learned to make tar on an industrial scale and used it to waterproof their famous longships, which allowed them to undertake long trips around Europe and the Atlantic, exploring and pillaging as they went.

Few cultures have sparked our collective imagnation as much as Vikings. They were Norse seafarers, who controlled a great part of Western and Northern Europe, conquering vast parts of today’s England, France, and Scandinavia. They weren’t afraid to stray even further away, going south to North Africa and east to Russia, Constantinople, and the Middle East — recent evidence shows they went as far as the Americas. They raided, pillaged, sold slaves, and established remarkable trade routes for a wide array of goods.

Although they were fierce and ruthless fighters, their main asset was their seafaring ability and the instrumental tool was the longship (not to be confused with the longboat). The longship’s design evolved and improved over the centuries, but maintained its core philosophy: long and slender, light and fast, the Viking longship was a wonder of its time, enabling the Vikings to spread far and wide.

Tar may have played a role in that, a new study suggests.

For over a hundred years, Northwestern Europe was a Viking fief. This German map depicts the most common expansion routes. It’s noteworthy that they also reached Greenland (several times) and North America.

The use of tar and other similar, resinous substances dates far back to prehistory. Archaeologists have found evidence of tar production in Scandinavia, but they weren’t sure how exactly it was produced — until they found funnel-shaped features, now identified as structures for producing tar. Now, archaeologists have found new evidence that the way tar was produced in Scandinavia changed dramatically in the 8th century, just as Vikings started raiding other parts of Europe. Writing in the journal Antiquity, Andreas Hennius of Uppsala University describes evidence of innovative tar production coinciding with the Viking expanse.

“Tar production developed from a small-scale activity … into large-scale production that relocated to forested outlands during the Viking period,” wrote Hennius. “This change … resulted from the increasing demand for tar driven by an evolving maritime culture.”

[panel style=”panel-default” title=”Tar” footer=””]Tar is a black or dark brown liquid distilled from wood or coal. Tar consists of a mixture of hydrocarbons, resins, alcohols, and other compounds. Today, tar is still a valuable commodity used in road-making and for coating and preserving timber.

In Northern Europe, tar is primarily derived from the wood and roots of pine.

Historically, it was produced in kilns which needed to be built close to the forest, usually from limestone. The kiln needs to have a very specific form, with a bottom that slopes into an outlet hole to allow the tar to pour out. The wood also needs to be split into small pieces and stacked very densely — if oxygen can enter, the wood might catch fire, and the production would be ruined.

After the fire is stacked and lit, it takes a few hours for the tar to start to pour, a process which can carry on for several days.

Tars needed to be built just right, otherwise the entire batch would have been destroyed. Tar kiln at Trollskogen in Öland, Sweden. Image credits: Sven boat builder.


Tar has been used to waterproof ships for thousands of years and is widely associated with (most) maritime cultures, and Vikings are no exception. In addition to an important trade commodity, tar would have allowed them to operate more ships safely, without needing repairs or overhaul.

The improved production method featured pits that could have made up to 300 liters of tar in a single batch. It was a massive, painstaking work, that required careful planning and execution.

As the Viking Age developed and seafaring intensified, so too did the demand of tar, but transitioning to the novel production technique meant they needed a different way to organize labor, a new way to manage forests, a new way to transport massive quantities of wood for the fires — it was a massive change on multiple technological and social levels.

This indicates that Vikings, while ruthless by all standards, were not mindless brutes — they were skilled and adaptable seafarers and were capable of remarkable technological and social contributions.

The findings were published in Archaeology.

(A) The larger of the two tar lumps found at Königsaue compared with (B) the maximum yield of tar produced with the raised structure method (RS 7). Credit: Scientific Reports.

Neanderthals were distilling tar 200,000 years ago well before humans

With their heavy brows and brutish appearance, Neanderthals (Homo neanderthalensis) seem to have been inferior to humans. But we all know looks can be deceiving. After all, it’s prejudices like these that can give birth to racism. Moreover, some people have even tried to use the scientific method to justify their racism.

Concerning our very close cousins, with each passing day, it seems like many of our assumptions, some subject of inter-species prejudice, are just wrong. One new study proves, for instance, that Neanderthals were distilling tar which they used to fashion tools some 200,000 years ago. It’s even questionable whether Homo sapiens even appeared around that time.

Could a brute make these?

(A) The larger of the two tar lumps found at Königsaue compared with (B) the maximum yield of tar produced with the raised structure method (RS 7). Credit: Scientific Reports.

(A) The larger of the two tar lumps found at Königsaue compared with (B) the maximum yield of tar produced with the raised structure method (RS 7). Credit: Scientific Reports.

Scientists learned of this fact after discovering tar beads in Italy, Germany, and other sites around Europe which were far older than the earliest signs of humans in Western Europe. The only explanation is that these were likely made by Neanderthals.

Tar is a huge technological breakthrough that enabled humans, and obviously, Neanderthals, to make superior tools. With this adhesive at hand, people could now assemble axes, hammers or any other machinery out of multiple parts.

There were some loose ends, though. We know that humans used to make tar ceramic vessels where tree bark was heated to around 350°C. The earliest archaeological evidence we have of ceramics is from 20,000 years ago, though.

The team of archaeologists at Leiden University, Netherlands, led by Paul Kozowyk investigated the lead by testing three scenarios for making tar from birch bark. The researchers were careful to only use technology that was available, from what we know of, to the Neanderthals. Ars Technica‘s Annalee Newitz describes one of the methods tested by the team:

“In the “ash mound” method, a roll of birch bark is heated under a pile of ash and embers. Tar is extruded into a birch bowl. In the “pit roll” method, a tube of birch bark is inserted into a narrow pit, and fire is lit on top. Tar drips from the roll onto a rock at the bottom of the pit. And finally, in the “raised structure” method, a birch bowl is placed in a shallow pit, under a screen woven from green willow wood. A roll of birch sits atop the screen and is then buried under dirt. Fire is lit on top of the dirt, slow-cooking the birch bark.”


Credit: Scientific Reports

All three methods rendered a couple grams of tar which is consisted with the findings from the archaeological sites, though they varied in complexity. The raised structure method required the most fire wood while the pit roll technique was simpler and required fewer resources but yielded little tar. Remarkably, they were also able to make tar at temperatures below 200 °C. This showed that Neanderthals didn’t need ceramics nor the technology to maintain a constant temperature to make tar.

It’s very likely that Neanderthals discovered tar making by accident. The researchers speculate in Nature Scientific Reports that it’s not unreasonable for Neanderthals to see tar dripping from bark thrown in the fireplace only for them to later attempt to manufacture their own after becoming impressed by its properties.

“In this way, they could develop the technology from producing small traces of tar on partially burned bark to techniques capable of manufacturing quantities of tar equal to those found in the Middle Palaeolithic archaeological record,” the authors concluded.

This is just the latest in a string of archaeological findings that demonstrate the intellectual prowess and social nature of Neanderthals. At the Croatian site of Krapina, anthropologists found a beautiful a set of eagle talons that included cut marks and were fashioned into a piece of jewelry. Neanderthals practiced cave painting and lit fires way before humans. The first instance of pre historic dentistry from about 130,000 years ago may have also been Neanderthal work. They even used manganese dioxide, today commonly found in batteries, to light fires some 50,000 years ago.

We can’t be sure that Neanderthals were the first to essentially invent glue. Maybe early humans in Africa independently arrived at the same discovery but there’s no evidence yet to back this up. In the meantime, no one can take this remarkable achievement away from Neanderthals who were far more complex than many care to give them credit.