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Brancaster Roman Fort

The Roman fort at Brancaster (also known as Branodunum) is thought to date to the early 200s AD. It probably functioned as both a fortified trading/supply base and, towards the end of Roman Britain. Possibly as one of the three 'Saxon Shore' forts defending Roman Norfolk against Saxon raiders (the others being at Burgh Castle and Caister on Sea).

SUMO Geophysics Director Dr John Gater originally visited the site in 2012 along with Channel 4's acclaimed Time Team. He was then invited back in 2018. This was to complete further geophysical investigations into the Roman Fort.


The Objective:

  • SUMO Geophysics to assess the state of preservation of archaeological remains inside the Scheduled Monument remains of Brancaster Roman Fort, Norfolk.

  • A secondary aim of the survey was to identify targets for selected excavation. This was to ground truth the Magnetic and Ground Penetrating Radar results. .


The Process:

  • Magnetic survey techniques were used both inside and beyond the fort.

  • High density Ground Penetrating Radar was used as a sample across a selected area of the fort.


SUMO's High Density Ground Penetrating Radar equipment at Branodunum.

The Result:

  • Magnetometry results confirmed the outline of the fort and the layout of interior features like barrack rooms and major buildings. The survey data also mapped extensive civilian settlements known as vicus which grew up outside the fort.

  • The vicus (already known to exist the west – discovered when houses were built in 1970-80s) was detected in the survey and seen to extend both east and north of the fort.

  • The Ground Penetrating Radar results provided, at the time, one of the clearest ever set of radar data demonstrating that the remains are very well preserved.

  • The resolution of the survey was of such a high quality that other features such as the Principia (found with a fountain in the courtyard and containing rooms with cellars), granaries for storing grain (with central pillars and columns showing in the data), a circus for exercising horses, as well as several other buildings, including one where below a floor the hypocaust heating (Roman equivalent of modern-central heating) was seen in the radar to still be intact.

  • A building on a different alignment to the fort buildings proved to be a mansion. This is much like a modern-day hotel and predated the construction of the fort.


Ground Penetrating Radar and Magnetometry data overlay of Branodunum - collected by SUMO Geophysics

SUMO has since returned to Brancaster to survey the whole of the interior area of Branodunum with High Density Ground Penetrating Radar and using Aerial drone – the results are currently being processed and more is to come!...

Survey techniques used in this case study...


Magnetic Survey


Ground Penetrating Radar (GPR)


Aerial Survey




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