Oswestry Castle Excavation 2015
In September 2015 we spent two weeks excavating part of Oswestry castle. This excavation consisted of a large trench (Trench 2) measuring 10 x 4m along the base of two standing walls that run East/West on the North side of the castle mound. The reason for choosing this spot was to determine if these two standing walls were part of the original castle structure and, if so, how much of them remained below ground. There was also a small scale excavation of the Northern side of these walls, limited by metal railings which enclose the top of the revetment walls surrounding the top of the mound.
It was quickly discovered that the irregular looking western wall section is part of the castle wall. It looks irregular because it is constructed of boulders and smaller stones embedded in lime mortar and is a actually a wall core. The outer ‘facing’ stones have been removed, possibly in the 17th century, to build some of the older buildings in the town centre. The more regular Eastern wall section was proved to be modern reconstruction and not part of the castle at all.
Beneath the turf was a layer of soil 20cm thick which contained modern rubbish such as bottle tops, broken glass, pottery and modern coins. This was probably brought in from elsewhere to level the site and to help establish the turf. Below this was a 1m deep layer consisting of numerous smooth stones, some up to football size, sandstone chippings and smaller pieces mixed in a very pale sandy soil. Archaeologists call this a demolition layer and it probably represents the unwanted parts of the castle walls left behind after the more valuable dressed stone was removed. There were very few finds from this layer and none of the finds could be dated earlier that the late 19th century. Once these layers were removed the castle wall below the ‘wall core’ seemed to be largely intact and well preserved. This was an exciting discovery because it suggests there is actually a considerable amount of the castle left under the surface. For safety reasons the trench could not be any deeper than 1.2m, but it did not reach the bottom of the wall so it may be much deeper than this. At the Western and Eastern ends of the trench there appear to be two wall returns striking South from the castle wall and at right angles to it. We can only speculate what these may be and this will be the focus of next years’ investigations.
A small excavation was also undertaken of the North (outer) side of this wall. This determined that the wall was 2.4m thick at his point and so is a substantial structure. The presence of well dressed sandstone facing stones suggest that underneath the embankment of modern concreted stones and soil there may well be a substantial part of the original exterior castle wall remaining. We could only uncover three courses due to proximity to the railing fence, enough to see that the sandstone blocks are set at 60 degrees to the vertical and are almost certainly part of an anti-batter or a splayed base.
Overall this was a very revealing excavation and clearly much more remains of the castle structure than anyone expected to have survived. However the
excavation did leave a number of questions unanswered; how deep is the floor level? Could this reveal evidence of how the castle was used? What was the overall layout of the walls? We are applying for a Heritage Lottery Grant to enable us to excavate again in 2016 to try and answer some of these questions.