Geraint welcomed Julian back to the group to follow up on the talk he had previously given to the group on the 18th February 2018 – “New Angles on Penybont”.
Julian told us that since his last talk he had been excited by the interest relating to the his study of the Common, so when he had a summer of brilliant weather from an aero/archaeological perspective, and he had acquired new software to play with, he was keen to come back to the Common and see what might emerge.
Julian said he wanted to be able to show how these amazing new tools could give new insight into landscapes that have hitherto been unreadable from the ground. The new techniques of photogrammetry were used. This enabled hundreds of photos of an area to be combined to build a 3-D digital model.
Julian explained that he wanted to demonstrate to us the power of this new technology by first looking at a range of sites that he has had previously looked at.
- Farm at Beulah was within a Roman Fort. An initial photograph showed this in outline but then using the power of photogrammetry this built into a 3-D image of the Fort and its Vicus, (civilian settlement),
- It was possible to see, with other images of the site, how different directions of light on the model could be brought together to show that ploughing had been carried out and where the old field boundaries were positioned.
These new techniques are beginning to reveal deeper insights into archaeological sites.
- Nearby it was possible to reveal
- Parch markings from a Roman camp
- Interior buildings and drainage marks
- Julian remarked how excavations of the site appeared to show that the drainage system went underneath the fort
One of the really useful features has been the fact that all of the information comes with very accurate GPS information.
- Near Offa’s Dyke Julian has been able to show evidence of a defended enclosure and the possibility of a pre-historic ridgeway that lead past the entrance to the enclosure.
- Before getting too carried away by this data it is important to recognize that the imagery is still to some extent superficial and confined to the surface of an area. There is still the need to carry out archaeological digging to get more evidence about the people who lived on these sites.
- Closer to home at Howey, near the Garden Centre and close to Caer Du, the techniques have revealed an enclosure and some evidence of an earlier circular enclosure.
- Near Strata Florida the basic photograph of an iron age hillfort did not identify anything of interest. In building the 3-D picture with colouring we begin to see house platforms with the reddish colour identifying the higher features and the green the lower ones.
- On Offa’s Dyke the 3-D model showed tracks that pre-date Offa. It showed how the Dyke was built digging out on both sides. It then identified a square feature underneath the Dyke. Archaeologists now think that there was a Roman Signal Station on the Eastern slope with a Beacon visible from the English side. These would have been very advantageous if they were under attack.
- At Llanbadarn Fawr Church field structures have been identified with significant ridge and furrow cultivation. More interestingly it shows a medieval field system apparently going underneath the Norman Church site. It suggests the possibility of a more ancient Celtic Holy site. When the Norman church was built, they may have moved from the possible Celtic site nearby to a drier situation and away from the boggy dampness. Without this 3-D modelling this would never have been discovered.
- At Painscastle Julian has been able to show a range of features around the Castle and the different elevations. He has also been able to identify features of rebuilding by Henry lll that shows the quarrying of the outer earthwork to make a new entrance.
- At Strata Florida a pre-historic site has been identified next to a garden area. There is a lot still to be found here and an adjacent dig has already taken place.
- On a ridge to the east, Julian has applied the same techniques to Lidar images taken from an aeroplane. These images effectively get rid of vegetation and even buildings and so reveal the underlying ground shape. After processing and exaggerating changes in height, a long sinuous earth bank was revealed for the first time. This had not been seen before because the changes in ground levels were very subtle. It is not thought to be a hill fort.
- At Abbeycwmhir Julian has exposed a number of features including a burial ground. In December 1644 Parliamentarians stormed the Abbey where a Garrison of Royalists were stationed. A number of defensive measures were taken across the grounds that showed up in Julian’s 3-D images.
Turning to Penybont Common and Coed Swydd Common Julian explained that he has laid his pictures over an Ordinance survey map. The ancient Roman Road and the three plantations provided reference points. Julian showed an image taken from the 1840’s Tithe map that identifies the Roman Road being used as a Toll Road.
He has used Lidar imagery to guide his drone survey:
“Lidar (Light Detection and Ranging)
Airborne lidar (light detection and ranging) measures the height of the ground surface and other features in large areas of landscape with a very high resolution and accuracy. Such information was previously unavailable, except through labour-intensive field survey or photogrammetry.
It provides highly detailed and accurate models of the land surface at metre and sub-metre resolution. This provides archaeologists with the capability to recognise and record otherwise hard to detect features.” https://historicengland.org.uk/research/methods/airborne-remote-sensing/lidar/
In using this system Julian has been able to work with 2m resolution, the best currently available for this area, but he is hopeful that in the near future 1m will become available. This contrasts with the 2cm resolution of Julian’s drone photos. He has been working with Clwyd Powys Archaeological Trust who have a particular interest in Penybont Common as it is one of the lowest upland commons in Wales.
The first image shown taken near the village shows fields surrounding the common but the enhanced image shows a medieval system of fields within the Common.
Going a bit further North on the Common the imagery shows further field systems going down towards the stream. Julian did not see this as an ‘open field system’:
“The open-field system was the prevalent agricultural system in much of Europe during the Middle Ages and lasted into the 20th century in parts of western Europe, Russia, Iran and Turkey. Under the open-field system, each manor or village had two or three large fields, usually several hundred acres each, which were divided into many narrow strips of land. The strips or selions were cultivated by individuals or peasant families, often called tenants or serfs. The holdings of a manor also included woodland and pasture areas for common usage and fields belonging to the lord of the manor and the church. The farmers customarily lived in individual houses in a nucleated village with a much larger manor house and church nearby. The open-field system necessitated co-operation among the inhabitants of the manor.” https://en.wikipedia.org/wiki/Open-field_system
The system here seems to suggest a tenant system where individual families managed an area for themselves. Some of the lines that emerge suggest that bracken was harvested. There has previously been some Archaeological research in this area which identified platforms in this area suggesting that there was a farm at Caertwch in medieval times – the only sign of habitation on the Common.
The 13th Century was a time when the climate conditions in this part of the world were favourable to growing crops and this was accompanied by a population explosion and there are no features on the Common that might suggest an older settlement. The small circular features shown on the imagery were cattle feeding stations not hut circles! The field systems identified would have been capable of supporting 20 to 40 households. There are however no signs of this level of habitation. Where have the people gone??
Julian then moved across the Common to the ‘circle of trees’, an old plantation. This is the area with the field system with the characteristic S shaped furrows. Here there are no platforms. The field systems extend down to the boggy bottom. The is about 1 km of field systems along the ridge which is very extensive and still we have the problem; where did the people live?
Perhaps the question is: where did they go? The 14th century in contrast to the 13th was a terrible time with poor harvests, famine, the ‘Black Death’ in 1349. An average of 30% of the population died of the plague having been weakened by the poor harvests and especially the great famine in 1315-17 when between 5% and 25% died. This had a dramatic impact on the social, economic and religious structures within the community. Priests who attended the sick often then became ill and died. The plague, often seen as a ‘punishment on the wicked’, consequently hit the clergy particularly badly. In this area the records are sparse but more generally there was a 1st pestilence in 1349, a second in 1359, and then again in 1370.
By 1400 there was considerable disquiet and the rise of Owain Glyndwr put further stresses on the population.
At some point, with these potentially multiple causes, the Lords of the Manor appear to have moved tenants off the land and replaced them with sheep that were seen as easier and more economical to manage. In this way the medieval field system revealed in this survey was abandoned.
Julian finished by saying that the Common here is quite unique and there is nowhere in Wales on this scale and history.
Finally, he mentioned an exhibition of his photos which are currently being displayed in the Radnorshire Museum with 100 photographs entitled ‘Marks in the Landscape’. The exhibition is on until Christmas.
The following set of photographs show, to some extent, the different ways that Julian has been able to manipulate images to identify features in the landscape that have archaeological significance. This first photograph is an ordinary image showing the landscape around Caertwch where we now know that there are platforms showing that this was a site of a small settlement around which there was a field system. This single image is flat and it can be quite hard to identify the features that lie within it.
The next three photographs show different manipulations that Julian has done combining many aerial photographs. The images then give a 3-D effect and by using colour and other techniques he can get spectacular results.
This next image is a close-up showing the platforms.
This next image is of the area around the ‘circle of trees’, one of the old plantations on the Common.
The final image is another single image of the area of land adjacent to the ‘circle of trees’ that gives a good impression of the field systems that were so extensive across the Common.
The next meeting of Liz Turner talking about the Domestic Craft will have been and gone by the time this is published. The first meeting of the New Year will now be on Monday 3rd February 2020 when Dr. Marion Evans will be talking about ‘The Romans in Radnorshire’. Hope you all have a great Christmas and Best wishes for 2020.