Oswestry Castle Excavation 2016
Following the successful 2015 excavation on top of the Castle mound the project applied for and received a Heritage Lottery Fund grant to excavate again in September 2016. This enabled us to put in two 4x5m trenches (Trenches 3 and 4) that extended the 2015 trench to explore the layout of the buried castle wall we uncovered in 2015, particularly the two returns at the East and West limits of Trench 2. The trenches were large because we knew from last year there is a considerable depth of overburden covering the remains of the castle and their size meant that we could ‘step’ the sides to reduce the risk of collapse.
After removal of the turf and a 20cm layer of topsoil we were faced with demolition material of sandy soil with mixed stone and boulders much like last year. We removed this material to a depth of nearly 1.5m, this limit again determined by safety considerations, but still did not reach a floor level. The bottom of trench 4 was probed with rods and resistance (a possible surface) was detected about 1.3m deeper than the bottom of the trench. This means that if there is a mediaeval floor at this point it is at least 2.8m below the current ground surface.
The finds from the top 20cm are similar to those of last year and are mostly 20th century. From the demolition layer several pieces of pottery were found some of which are probably medieval, including some with a bright green glaze, although we are awaiting an expert pottery analysis to properly identify them. A number of musket balls were also found, which is not surprising as Oswestry castle was subject to a siege during the Civil War during which the town was badly damaged.
The excavation revealed two substantial walls of similar construction to last year and although somewhat damaged in places they were overall in very good condition. The interior walls are of roughly dressed sandstone but the small area of exterior walls we exposed are of uniformly sized and well-dressed blocks. The walls were running parallel to each other, are 2.4m to 2.5m wide and approximately 8m apart, and at right angles to the wall exposed in 2015. This suggests that this part of the castle was a square or possibly rectangular structure, and is unexpected because the published information suggests that Oswestry castle was a ‘shell’ Keep, a different type of structure altogether. Also it appears we are excavating what is likely to be a basement in the interior of the structure which would explain why the overburden is so deep.
The right hand trench (Trench 4) exposed the external part of the Eastern wall and we were able to excavate this to a depth of 0.7m. We could not excavate further because this was at the very edge of the trench, but we discovered that the sandstone blocks forming the outer dressed surface of the wall set at an angle of 60 degrees to the vertical, similar to those uncovered on the North face last year. This finding strongly suggests that the structure stood on a substantial splayed base. Because of these findings we are drawn to the conclusion that the parts of the structure we have exposed this year and last year suggest a tower keep or Donjon of probable 12th Century date set on an impressive splayed base.
This was a significant and unexpected finding which has changed the direction of the research project. The available Historical literature describes this castle as a shell keep not a Donjon and we welcome the opportunity for further excavations to discover the Keep’s plan and structure more fully. With this is mind we are applying to the Heritage Lottery Fund for a further grant to allow us to excavate on the site for another two years, from September 2017 to September 2019.