No Atomic Blast. Fire Melted the Stones of Iron Age Forts Say Investigators

Ancient Origins

In Scotland, archaeologists believe that they have solved the mystery of an Iron Age fort in which stones had melted in a process termed vitrification. The team of experts studied the vitrified fort, known as Dun Deardail, in the Highlands, near Ben Nevis and have concluded that they can explain how its stones became molten and melted.

 Vitrified Forts
Dun Deardail has been dated to have been built around 500 BC, based on carbon testing. It was occupied by the Celts and later by the fierce Picts who used it as a fortress. The outline of the original fort can still be seen today as grassy embankments and it sits a-top a hill, that once had strategic significance in the area. It is perhaps one of the best known of the vitrified forts in Scotland, along with Ord Hill, and has fascinated people for centuries. Many people visit the spectacular site set in stunning landscape every year.

Dun Deardail. At the top of this hill is the vitrified Iron Age fort. ( CC BY SA 2.0 )

There are many similar vitrified forts in France and Ireland. It is estimated by the National Geographic that there are about 70 vitrified forts in Scotland and 200 in total in Europe. Scientists believe that to vitrify stone slabs that a heat of 2,000 degrees Fahrenheit or 1,100 degrees Celsius , is required. The question as to how Iron Age people managed to ignite such conflagrations with their crude technologies and limited capabilities has only added to the mystery.

The experts from the Forest Enterprise Scotland, working with Stirling University and local volunteers, believe that they have solved the enigma, reports the Scotsman. They believe that a large-scale wooden structure over the stone walls was set alight and the blaze reached such a temperature that it burned the stones. Have the team solved the mystery of the vitrified forts?

Dun Carloway Broch, Lewis, Scotland. Another fort that has areas of vitrification. ( Public Domain )

Solving the Mystery
In order to solve the riddle of the vitrification of forts in Scotland and elsewhere in Europe, a series of investigations have been carried out since at least the 1930s. These tried to duplicate the conditions that would have led to stone vitrifying. None of their results were especially convincing and the reasons for the melting of stone forts continued to be a mystery. The failure to provide a satisfactory theory encouraged all kinds of wild speculation. For example, the popular author, Arthur C Clark argued that the stones were melted and fused by some Iron Age superweapon if not an early atomic bomb.

Now the team led by an archaeologist from the University of Stirling have offered what they believe is the most plausible explanation for the phenomenon of the vitrification of stone citadels. The study has shown that a timber superstructure, which included ramparts and towers, was set alight and the resulting blaze heated the stones. The fire was so intense that is was able to melt stones because of the anaerobic environment that developed as the flames burned down into the stones. The absence of oxygen in the anaerobic conditions, made the fire much more intense and allowed it to reach the temperatures that would have burned the slabs until they melted and fused

Fused stones. This was once part of a wall to the original hill fort at Dunnideer which gave the hill its name. ( CC BY-SA 2.0 )

The team is not only excited by the potential discovery of the cause of the vitrification process but also by the insights that it offers into the nature of Iron Age forts and society. The theory can help us to visualize what these forts looked like. They were impressive bastons with stone walls and according to Matt Ritchie, archaeologist with Forestry Enterprise Scotland they had ‘ roofed rampart walls many metres high’ . He also believes that the extensive wooden structures were used to store the precious food supply of the community.

 It seems that the archaeologists and the team of volunteers have explained one of the most perplexing mysteries from the Iron Age. They have offered a rational and plausible explanation for the vitrification of forts without the need for far-fetched theories. However, according to Ritchie ‘ of course the mystery of why the forts were burned remains unresolved’ . It has been speculated that they were burned during war, as part of a religious ceremony or to mark the death of a monarch.

Top image: Dunnideer Castle, built on the site of a hillfort with a remaining vitrified rampart. ( CC BY-SA 2.0 )

By Ed Whelan

Romans, quaking in their Sandals After an Attack by Boudica, built a Massive Fort to Defend London

Ancient Origins

Around 60 AD Queen Boudica of the Iceni (a Celtic clan) attacked and razed London, a Roman city of ancient Britain. Now, researchers have just announced that in response to Boudica and her warriors’ wild revolution, the terrified and shamed Romans built a fort with ditches 10 feet (3.05 meters) deep, walls 10 feet high, palisades, and a platform from which to repel attacks.

Boudica (also spelt Boudicca and Boadicea) was an imposing, even terrifying sight, according to the Roman historian Cassius Dio, who described her and the destruction her forces wrought:

“...a terrible disaster occurred in Britain. Two cities were sacked, eighty thousand of the Romans and of their allies perished, and the island was lost to Rome. Moreover, all this ruin was brought upon the Romans by a woman, a fact which in itself caused them the greatest shame....But the person who was chiefly instrumental in rousing the natives and persuading them to fight the Romans, the person who was thought worthy to be their leader and who directed the conduct of the entire war, was Buduica, a Briton woman of the royal family and possessed of greater intelligence than often belongs to women....In stature she was very tall, in appearance most terrifying, in the glance of her eye most fierce, and her voice was harsh; a great mass of the tawniest hair fell to her hips; around her neck was a large golden necklace; and she wore a tunic of diverse colours over which a thick mantle was fastened with a brooch. This was her invariable attire.”

The Snettisham Torc (a golden necklace) like one Boudica might have worn. (U. of Chicago)

No wonder the terrified Romans built such a massive fort.
“Positioned over the main road into London, commanding the route into the town from London Bridge and overlooking the river, the fort would have dominated the town at this time, perhaps reflecting the absence of civilian life and the utter destruction wrought by the native Britons on Roman London,” says the Museum of London Archaeology in a short article.

• Boudicca, the Celtic Queen that unleashed fury on the Romans
• Is Celtic Birdlip Grave the Final Resting Place of Queen Boudicca?

The British government, in excavations at Plantation Palace on Fenchurch Street, uncovered the wooden and earthwork fort, which covered 3.7 acres. It measured 3 meters (9.84 ft.) high and was reinforced with growing turf and interlacing timbers. There was a fighting platform with palisade and towers at the gateway on the top of the bank.
For extra protection, the fort was enclosed by double ditches, 1.9 (6.2 feet) meters wide and 3 meters (9.84 ft.) deep. A press release from the Museum of London Archaeology (MOLA) called the ditches “an impressive obstacle for would be attackers.”

Reconstruction of a Roman defensive position. (MOLA)

Apparently, the fort was a temporary, emergency structure that was not meant to be occupied long-term and was used to re-establish and reconstruct the important trading post. MOLA says researchers found evidence of tent use in the fort as opposed to permanent barracks. It was in use for only 10 years.
Julian Hill, Roman London Expert at MOLA, said in a press release: “The discovery of this early Roman fort provides precious new information about how the Romans re-established control of Britain following Boudica’s damaging blow. It also demonstrates the strategic importance of London at this time.”

‘Boadicea Haranguing the Britons’ by John Opie. (Public Domain)

The museum’s website about the find states:

“The Roman army were experts in construction; proficiently sourcing local materials from nearby woods and even using debris from buildings burnt in the revolt. It is estimated that a fort of this size would have housed a cohort of approximately 500 men but could have been built by hand in a matter of weeks, perhaps with the help of captive Britons. Archaeologists uncovered a pick axe and a hammer, tools that would have been available to the army for building projects.”

• Tomoe Gozen - A fearsome Japanese Female Warrior of the 12th Century
• Metal detectorist uncovers Roman treasure hoard in England

The fort had roads, storage and administrative facilities, a cookhouse, a granary, and a latrine. Very few artifacts were found, though archaeologists did turn up part of a helmet and some mounts from horse harnesses.

Militaria from Plantation Place Roman fort. (MOLA)

“A number of major infrastructure projects contemporary with the fort point to the army playing a crucial role in this rebuilding, providing labour and engineering expertise for roads, a new quay and a water lifting machine, all vital for trading and civilian life to thrive once again,” the article states.
About 60 years after Boudica’s attack, the Romans built Cripplegate fort, then in the 3rd century a big wall was built around London. Archaeologists are searching for forts or other defensive structures from the intervening periods.

Timber lacework from vallum of the fort. (MOLA)

Featured Image: Reconstruction of Plantation Place Fort. Source: MOLA
By Mark Miller

Oldest Roman Fort Protected Soldiers from 'Infamous Pirates'

Charles Q. Choi
Live Science

Lidar (the laser equivalent of radar) revealed the oldest known Roman military camp called San Rocco (C). Also shown are the Roman military camps Grociana piccola (A) and Montedoro (B). Scale bars: 100 m. Credit: Image courtesy of Civil Protection of Friuli Venezia Giulia. View full size image

Using airborne laser scanners, researchers have discovered ancient fortifications in Italy that make up the oldest known Roman military camp, where soldiers may have fought pirates more than 2,000 years ago.
This camp may help reveal clues about how the Romans developed their army, and the structures might have served as the foundations of the modern Italian city of Trieste, the researchers said in the new study.
The Roman army was among the most successful militaries on Earth, and helped to create an empire that spread across three continents. A key factor behind the strength of the Roman army was the art of building orderly military camps.

The origin of the Roman military camp remains unclear, the researchers said. Until now, the oldest confirmed Roman military camps had been located in Numantia and Pedrosillo in Spain, which date to about 154 B.C. and 155 B.C., respectively.
But the recently discovered Roman camp described in the new study was probably built in 178 B.C., thus predating the oldest Spanish camps by decades, the researchers said. They suggested that these newfound fortifications may have provided the foundation for the colony of Tergeste, the ancestor of the modern city of Trieste. [In Photos: Ancient Roman Fort Discovered]
"They are probably the most ancient examples of Roman camps in the entire Roman world," lead study author Federico Bernardini, an archaeologist at the Abdus Salam International Center for Theoretical Physics in Trieste and the Fermi Center in Rome,told Live Science.
Looking with lidar
The scientists analyzed the Bay of Muggia, the innermost part of the Gulf of Trieste, located near Italy's northeastern border with Slovenia. This is one of the most protected natural harbors of the northern Adriatic coast, making it a good place to build a settlement, the researchers said.
The team used a laser scanner mounted on a helicopter to scan the area with lidar (short for "light detection and ranging") — the laser equivalent of radar.
"Lidar is like a new telescope, which allows you to see worlds that are not visible by the naked eye," said study co-author Claudio Tuniz, a physicist at the Abdus Salam International Center for Theoretical Physics in Trieste and the Fermi Center in Rome."It can reveal large ancient archaeological structures hidden under trees or other landscape features."
"It can provide unexpected results, even in relatively urbanized territories investigated for a long time," Tuniz told Live Science. "With lidar, we discovered in a few months more prehistoric archaeological structures than those discovered during one century of work with conventional archaeological methods."
With the help of lidar, ground-penetrating radar and archaeological fieldwork, the scientists discovered the remains of a military camp at San Rocco.
"After seeing the image of the first Roman camp, [Bernardini] ran to the site, 30 minutes from our institute, to search for direct evidence," Tuniz said. "Sure enough, after a brief stroll through the site, he found clear signatures of the Roman period, such as the characteristic hobnails used to make the military shoes of Roman soldiers and fragments of Roman amphorae, widely used to store oil, wine and other food products."
This military camp was relatively large — greater than 32 acres (13 hectares) — and was defended by imposing fortifications, such as wide ramparts up to about 80 feet (25 meters) wide, the researchers said in the new study. It was located on a hilltop in a strategic central position about 1.2 miles (2 kilometers) from the innermost present-day shore of the Bay of Muggia, they said.
Two minor forts flanked the main military camp. One rested on a large terrace on Montedoro ridge, overlooking access to the Rosandra River, while the other, at Mount Grociana, overlooked both the Bay of Muggia and routes leading from the Gulf of Trieste to what is now Slovenia and Croatia.
Infamous pirates
This is the first Roman military camp discovered in Italy, and the newly discovered fortifications were probably created during Roman wars against people known as the Histri, who controlled the nearby Istrian Peninsula, the researchers said.
"Their objective was also to protect the new neighboring city of Aquileia from the incursion of the Istrian peoples," Tuniz said. "Its port was an important emporium for the trade of wine, olive oil and slaves. Aquileia would later become one of the capitals of the Roman Empire."
The Roman historian Livy described the Histri as infamous pirates. [The 10 Most Notorious Pirates Ever]
"According to Livy, in the first phase of the conflict, two legions of Roman Republic were defeated by the Histri, and the camp was lost," Bernardini said. "Livy reported that the Histri found a lot of wine inside the camp and got drunk, and this helped the Romans reconquer the camp very easily."
Pottery fragments at San Rocco revealed that the site dates to between the end of the third century B.C. and the first decades of the second century B.C. "Investigation of the sites will be crucial to study early Roman military architecture and the origin of Roman military camps," Bernardini said.
The age, size and location of the San Rocco site correspond to a military camp Livy wrote about that was built in 178 B.C., the researchers noted. This was "a crucial historic period at the borders of the Roman Republic," Tuniz said.
Ancient records suggest that the Romans may have used the camp until the foundation of Tergeste, the scientists added.
"Many European cities originated from ancient Roman military forts, including Bonna, or Bonn; Vindobona, or Vienna; Eburacum, or York; and Argentorate, or Strasbourg," Tuniz said.
The scientists plan to do full-scale archaeological excavations at these sites. They detailed their findings online March 16 in the journal Proceedings of the National Academy of Sciences.

Let in the Light: Ancient Roman Fort Designed for Celestial Show

by Owen Jarus
Live Science

The fort was constructed during the rule of Roman Emperor Hadrian (reign A.D. 117-138). It was part of a system of fortifications that protected the frontier of Roman Britain. Credit: PHB.cz (Richard Semik) | Shutterstock.com

The gateways of an ancient Roman fort in Britain are roughly aligned with the light from the sun during the summer and winter solstices — a design that would have resulted in a striking scene on the shortest and longest days of the year, a researcher says.
The fort had four gateways facing one another. During the summer solstice, the sun would rise in alignment with the fort's northeastern and southwestern gates, and set in alignment with its northwestern and southeastern gates, the researcher reported in the new study.
During the winter solstice, the sun would rise in line with the fort's southeastern and northwestern gates, and set in line with the fort's southwestern and northeastern gates. [In Photos: Amazing Ruins of the Ancient World]

Moreover, the four towers of the garrison seem aligned to cardinal directions," Amelia Carolina Sparavigna, a physics professor at the Politecnico di Torino (Polytechnic University of Turin) in Italy, wrote in the study, published Dec. 17 in the journal Philica.

The ruins of the Roman fort in Britain by Hardknott Pass are roughly aligned with the light of the solstice sun.
Credit: Satellite image copyright Infoterra Ltd & Bluesky, courtesy Amelia Carolina Sparavigna

View full size image

The fort's ruins are located near Hardknott Pass in Cumbria, England, and offer a commanding view of the sprawling Eskdale Valley. Built during the reign of Emperor Hadrian, who ruled from A.D. 117 to 138, the structure was part of a series of fortifications that once guarded the Roman frontier in Britain.
Sparavigna used online software to calculate the angles at which the solstice sun rises and sets at the fort. She then used satellite maps available on Google Earth to determine how the rising and setting solstice sun compares to the fort's features.
"This image is very interesting, because we can easily imagine the sun passing through the four gates on solstices," Sparavigna said.
The summer solstice (which last occurred on June 21, 2014) represents the longest day of the year, when the sun appears at its highest point in the sky. The winter solstice (which last occurred on Dec. 21, 2014) represents the shortest day of the year, when the sun appears at its lowest point in the sky.

High-resolution images of the fort and its topography are available through Google Earth. These images were used along with the solstice sunrise/sunset calculations to discover the alignments.
Credit: Satellite image copyright Infoterra Ltd & Bluesky, copyright Google

View full size image

Sun gods?
But the reason for the fort's celestial alignment remains unclear. In her paper, and in an email to Live Science, Sparavigna noted that she is not an expert on Roman religion. However, she did offer some ideas that might help to explain the alignment.
"An orientation of sacred places to sun and sky is common to several religions," Sparavigna told Live Science in an email. It is "quite possible that the Hardknott fort has a symbolic homage to the sun," she said. "The god could be Sol, the ancient Roman god of the sun, which evolved [into] Sol Invictus (a deity whose name means "unconquered sun")."
Another possible link could be with Mithra, a god of light, "whose mysteries were a religion popular in the Roman army," Sparavigna wrote in the study. The worship of Mithra originated in Persia but became popular throughout the Roman Empire. 
Sparavigna also noted that there are several Roman towns in Italy that have alignments with the solstice sun. Additionally, the town of Timgad, in northern Africa, is aligned with the direction of the sunrise on the birthday of the Roman Emperor Trajan, who reigned from A.D. 98 to 117.