Runnymede Explored: geophysics at Ankerwycke

Published: 14 June 2021

Last update: 14 June 2021

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This blog post is written by Runnymede volunteers, Archaeology volunteer team Runnymede volunteers Archaeology volunteer team
Volunteers undertaking geophysics at Ankerwycke

Thanks to funding from the National Lottery Heritage Fund, for the Runnymede Explored project, the National Trust is transforming the way people experience the Runnymede site in Surrey. Visitors will be able to enjoy improved access to the historic site and surrounding areas, with newly-created interpretation and engagement with the local community at Runnymede and Ankerwycke. A key aspect to this is archaeology; Andrew Hutt from the Berkshire Archaeological Society and Hannah Potter, Project Archaeologist for Runnymede Explored and Surrey County Archaeological Unit, explain what’s been happening.

It is over 800 years since feudal barons forced King John to seal Magna Carta at Runnymede, on the banks of the Thames, near Windsor. This 'Great Charter' established the principle that everyone is subject to the law, even the King. It also guaranteed the rights of individuals, including the right to justice and the right to a fair trial. Magna Carta remains one of the world’s most important and influential documents and Runnymede is widely acknowledged to be the birthplace of modern democracy. On the opposite bank of the river, Ankerwycke is home to the remains of a Benedictine priory and a famous ancient yew tree, said to be 2,500 years old. 

A tale of two sites and one river

On the western bank of the River Thames between Staines and Old Windsor lies Runnymede, a name you will recognise as a site renowned for its outstanding international significance as the ‘birthplace of modern democracy’, being the recorded location of the sealing of Magna Carta by King John in 1215. The significance of Runnymede as a commemorative landscape is demonstated by the numerous memorials within and surrounding it. Additionally, the lack of development along this stretch of the Thames is reflected in the site’s popularity as a visitor destination today.

The Jurors at Runnymede, Surrey
The Jurors at Runnymede, Surrey
The Jurors at Runnymede, Surrey

On the eastern side, Ankerwycke possesses a quite different but no less interesting character - you might have heard of the Ankerwycke Yew, which at over 2,000 years old is believed to be the National Trust’s oldest tree. However, you might not realise that at the heart of Ankerwycke lies a Scheduled Ancient Monument representing the remains of a medieval priory, later adapted into a Tudor mansion and then a 19th-century designed landscape. We say might not, because little remains to be seen above the grazed tranquil riverside meadow.

A view of the Priory ruins at Ankerwycke
A view of the Priory ruins at Ankerwycke
A view of the Priory ruins at Ankerwycke

The Runnymede Explored project has had a stuttering start due to challenges we are all too aware of, but we were incredibly lucky that over the last two years and between lockdowns the Berkshire Archaeological Society successfully carried out several geophysical surveys at Ankerwycke. These surveys have helped reveal a whole host of surviving features buried beneath the grass of Ankerwycke showing how different the site was to the one you see today. A number of historic maps, paintings and photos of the site and of various now-vanished buildings do exist, such as sketches of the ruins by J. W. Turner in c1811 and 1940s aerial photos from the Historic England archives.

The geophysical results have helped understand the different phases suggested in map regressions and verify some of the written records and artistic depictions, but they also reveal how much of the site's varied history has been lost completely or just buried out of sight.

The Berkshire Archaeological Society undertook two different types of survey; one using a gradiometer, which measures changes in the earth’s magnetic field and the other using a resistivity meter, which measures changes in the earth’s resistance. The two different approaches give slightly different results, allowing a more complete picture of buried features to be mapped and interpreted.  

Geophysical survey results

The work helped shape the idea of four distinct landscapes preserved within the soil at Ankerwycke, which can be linked to subtle (or not so subtle) visible features around the site today. 

Plot showing 2020 resistivity survey results and interpretation of features
Plot showing 2020 resistivity survey results and interpretation of features
Plot showing 2020 resistivity survey results and interpretation of features

A medieval landscape with a priory guarded by a gatehouse

The priory was sited on an isthmus was divided by a water course, the Priory Field Channel, which is visible today and probably served as a bulk water supply to the priory and as a land drain along with the fishponds. The geophysics has revealed the alignments of priory buildings spread between the upstanding remains and the Yew tree, a garden and possibly of bridges over the channel. This landscape lasted from when the priory was established around 1160 until it was dissolved in 1536 during the Dissolution of the Monasteries. The geophysical survey has also revealed what could be ridge and furrow farming, evidence from when the site was in transition from priory to mansion. 

A Tudor to Georgian landscape

 This was a slight amendment of the medieval landscape and lasted from around 1551 until around 1800. The focus of this landscape was the Tudor period mansion built by Thomas Smith, which was a development of the priory buildings and the garden as revealed in the geophysics. Evidence suggests that the Priory Field Channel was filled in sometime during these 250 years.  

A Georgian to early 20th-century landscape

Ankerwycke House, a Georgian mansion, was built on land north of the priory in 1805 following the purchase of Ankerwycke by John Blagrove. The extant buildings of the priory and Tudor mansion were reduced to picturesque ruins within a pleasure ground connected to the mansion by the avenue of Grey Poplars that still survive today.  A number of boat houses, and a Picnic House were built along the riverbank. 

Ankerwycke House and swimming pool complex, late 1940s. Britain from Above (EAW002309)
Ankerwycke House in the 1940s
Ankerwycke House and swimming pool complex, late 1940s. Britain from Above (EAW002309)

A 20th-century landscape

During the late 1930s, the Georgian mansion was used as a nightclub. The key feature in this landscape was the swimming pool complex with a pool, changing rooms and a boiler house in Priory Field along with a landing and steps on the riverbank; these structures have since been demolished and little evidence can be found above ground. However, the geophysics revealed that features had been filled in rather than removed. 

The work of Berkshire Archaeological Society at Ankerwycke has shown that though the archaeology may be out of sight, it will now not be forgotten, and you can read the full survey report via Heritage Records Online. As the project moves forward over the coming year, archaeological investigation will continue at both Runnymede and Ankerwycke, working with volunteers from the local community to enhance our knowledge of these important sites.

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