The playing fields at Dwr-y-Felin Comprehensive Upper School, Neath, lie over the site of the Roman auxiliary fort of Nidum which was first discovered in the 1950s. Some areas of the fort and the civil settlement that lies beside it have been explored since then, giving us a general picture of its size and layout and suggesting that the defences of the earliest, timber fort of the 1st century were in a slightly different position from the later stone fort which was built in the early 2nd century and occupied sporadically at least into 3rd century. However, the evidence was not good enough for Cadw to be able to extend the scheduled area of the stone fort to cover all of these possible earlier defences.
In 2010, the school needed to build a new teaching block in the playing field. The site chosen was outside the scheduled area but still within the area where we thought there was probably archaeology. For this reason the local authority, Neath Port Talbot County Borough Council, commissioned the Glamorgan-Gwent Archaeological Trust to carry out the necessary excavation. The results of this excavation have given us a whole new understanding of the early fort and the area outside its north-west gate.
The defences of the timber fort (or perhaps two successive timber forts) consisted of four parallel ditches and a rampart. Within the excavated area there was also an interval tower projecting beyond the rampart. Three of the ditches were about 2m wide at the top and the fourth was about 1.5m. They each sloped down in a V-shape to give a width of 0.2m. The combined width of all together was greater than12m, which would have proved a formidable obstacle. However, we cannot be certain that all of them were in use at the same time. The outer ditch was interrupted at the point where it met the road coming out of the north-west gate on a causeway about 4m wide. If the fort was turned to face enemy territory, this will have been the road out of the main gate (the porta praetoria), but it does not seem to have been laid in this form until the stone fort was built, since underneath it was an extensive area of metalling that probably went with the timber fort. This must have been a particularly useful feature as when the outer ditch went out use, the whole of the section to the south-west of the causeway and the terminus of the section to the north-east was sealed by a cobbled surface, probably a hardstanding outside the gate.
The rampart, which ran alongside the edge of the innermost ditch was about 6.7m wide. The front was supported on a stone foundation made from rubble and cobbles and the back was faced with turf. In between, the core was made from a mixture of soil dug from the ditch and clay. About half way between the gateway position and the corner of the fort was an interval tower about 3.2m by 2.8m. Its position was marked by the remains of three large postholes and by breaks in the stone foundation of the rampart (the posthole at the fourth corner was indistinct). Two of the posts were set into the front edge of the rampart but, possibly uniquely in Britain, the other two were set into the ditch line on the outside of the rampart. This tower would have allowed soldiers to shoot at anyone attacking the gate.
Another unique feature was found in the face of the rampart, between the interval tower and the gateway. The line of the stone foundation had been broken to form a recess projecting into the rampart core with its ends angled inward on each side, with at the back what seems to have been a trench for a palisade to stop the rampart from collapsing (and possibly to support a lifting mechanism). The purpose of this feature is unknown – could it and a pit dug near the gateway perhaps be related to the soldiers extracting gravel from the earlier ditches for the later fort?
As usual a road (the via sagularis) ran round the fort inside the defences. Between it and the rampart were the remains of a cluster of seven ovens, with another lying about 12m away. They were represented by circular bases of flagstones or cobbling enclosed by walls in the local sandstone. One had been replaced by a rectangular oven base. The overlying soil in this area contained a lot of charcoal, probably the remains of fuel raked out the ovens.
Outside the fort, the team found very few traces of activity apart from a building that had already been discovered during a trial excavation in the 1990s, so we still have only a limited understanding of the civil settlement.
Now the excavation is finished, we will have to write up the results after studying the records made on site and the finds. One interesting discovery we have already made about the pottery is that a mortarium (a bowl for grinding and mixing food) was produced by the same maker as a mortarium from the fort at Loughor thirteen miles away to the west.
Watch videos of the excavation at