Archaeologists found a lost Roman fortlet in Scotland

The team made the historic discovery by measuring tiny changes in Earth's magnetic field.
An artist's impression of Watling Lodge fortlet, which also once stood along the Antonine Wall, and would have been similar to the fortlet discovered near Carleith Farm.
An artist's impression of Watling Lodge fortlet, which also once stood along the Antonine Wall, and would have been similar to the fortlet discovered near Carleith Farm. Historic Environment Scotland

Archaeologists in western Scotland have found the foundations of a Roman fortlet dating back to the Second Century CE. According to the government-run historic preservation commission Historic Environment Scotland, this fort was one of 41 defensive structures that was built near the Antonine Wall, one of Scotland’s six UNESCO World Heritage Sites.

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This fortified wall made of mostly wood ran for roughly 40 miles across Scotland as part of the Roman Empire’s unsuccessful attempt to extend its control throughout Britain from roughly 410 to 43 CE. The Antonine Wall was defended as the northernmost frontier of the Roman Empire. Emperor Antoninus Pius ordered the building of the wall in 142 CE as a one-up to his predecessor Hadrian. The famed Hadrian’s Wall was built in the 120s CE about 100 miles south of the Antonine Wall.

The Romans called the people living in Scotland “Caledonians”, and later named them  the Picts after a Latin word meaning “painted people,” in reference to their body paintings or tattoos. The Romans retreated to the Hadrian Wall in 162 CE after 20 years of trying to hold a new northern line at the Antonine Wall.

In 1707, antiquarian Robbert Sibbald said he saw the fortlet in the area around Carleith Farm in West Dunbartonshire. During the 1970s and 1980s, excavation teams looked for it but were unsuccessful.

An archaeologist stands in a green filed in Scotland and uses  a non-invasive geophysical technique called gradiometry.
Archaeologists used a non-invasive geophysical technique called gradiometry to find the fortlet’s foundation. CREDIT: Historic Environment Scotland.

New technology allowed Historic Environment Scotland’s archaeological survey team to find the buried remains. The team used a geophysical surveying technique called gradiometry to peer under the soil without excavating. Gradiometry measures small changes in Earth’s magnetic field to detect buried archaeological features that can’t be seen from the surface. It identified the base of the fortlet, which remains buried under the ground. Turf would have been laid on top of this base. The team found the fortlet in a field near Carleith Primary School.

The fortlet would have been occupied by 10 to 12 Roman soldiers who were likely stationed at Duntocher, a larger fort nearby. The fortlet would have been made up of two small wooden buildings.

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“It is great to see how our knowledge of history is growing as new methods give us fresh insights in the past,” Riona McMorrow, deputy head of world heritage at Historic Environment Scotland, said in a statement. “Archaeology is often partly detective work, and the discovery at Carleith is a nice example of how an observation made 300 years ago and new technology can come together to add to our understanding.”

While up to 41 fortlets may have once lined the Wall, only nine have been found thus far. This new discovery marks the 10th known forlet, and Historic Environment Scotland is currently reviewing the site’s designation to ensure that it is protected and recognized as part of the Antonine Wall.