Archaeology Tuesdays – Purwell Bathhouse

In the early 1880s, a tenant farmer of William Ransom found pieces of ‘brick’ on the surface of a field close to Purwell Mill. When Ransom visited, he found Roman pottery, brick and tile. In November 1884, he began digging and found a concrete floor just 0.76 m below the surface. He soon discovered a furnace for heating an under-floor heating system that fed three rooms. Beyond these were more rooms and a corridor.

He recognised that he had found a Roman bathhouse and assumed that it was part of a villa, a large country house. Traces of burning, animal bones and oyster shells covered all the floors. Ransom thought that this showed that ‘some semi-barbarous tribe took possession and dwelt there’. The coins he found in it run from Gallienus to Valentinian II (AD 253-392), while others found nearby included one of Septimius Severus (193-211).

Percival Westell, curator of Letchworth Museum, decided to investigate the site further in the autumn of 1921. His team found the site of Ransom’s excavation and located a tiled corridor about 2 m wide. The finds they made were like those found in 1884, but they decided that the burning was a result of the buildings being destroyed by fire. Walking north of the site of the excavation one afternoon, the team found Roman pottery several hundred metres away, suggesting the site of a second building.

The Cambridge University Committee on Aerial Photography’s aerial photographs from July 1960 show the walls of the building. They reveal that the walls do not extend far beyond those that Ransom found: what he discovered in 1884 was an isolated bathhouse and the main dwelling must have lain elsewhere. The second site discovered by Letchworth Museum in 1921 was perhaps the location of the dwelling. The North Hertfordshire Archaeological Society did fieldwalking north of the bathhouse site in November 1978 and found more worn Roman pottery. Whether this was in the same place as the 1921 discoveries is unclear.

Over the years, illegal metal detecting has stripped the site of metalwork. Some detectorists brought coins into Letchworth Museum, including a coin of Antoninus Pius dated 145 to 161. Mark Curteis, then Assistant Curator of Letchworth Museum, re-examined all the coin finds from the site and concluded that they fall into two groups. One shows activity in and around the bathhouse, which probably began around the year 200. By the 330s, it had gone into decline but continued into the 380s or 390s. The second group of coins derives from a hoard, which Ransom excavated but did not recognise as such (although Westell later did). It dates from the period of the breakaway Gallic Empire of Postumus and his successors (261-274) and was buried in the mid-270s. The person who buried it never came back for it because coins of this period ceased to be legal tender in the later 270s.

Councillor Sam Collins walked around the field early in 2021 and discovered more Roman tile. He contacted the museum and organised fieldwalking one Saturday in September. Most of the finds consisted of pieces of Roman roof tile. There was very little domestic pottery and virtually no oyster shell, both things common where people were living. If this had been a villa site, where was the rubbish left by the people who had lived there?

There is perhaps not a villa at Purwell at all. The bathhouse is low-lying and damp, as Ransom observed in 1884. There is a risk of flooding from the nearby Ninesprings, which suggests an alternative explanation: similar isolated bathhouses close to water have been interpreted as parts of a nymphaeum. This was a temple dedicated to a spring or river, and the bathhouses used water blessed by the nymphs who lived there. A second building, visible on aerial photographs, stood on the hill-spur overlooking the bathhouse and could have been the temple. The burning discovered in 1884 and 1921 could then have been the deliberate destruction of a pagan site by angry Christians in the fourth century, something that has been found on other temple sites.

Questioning received wisdom – the things we think we know to be ‘facts’ – is always good. It is how we make progress, improve knowledge, and increase our understanding of the past. Just because something has been accepted for years does not mean that we should regard it as written in stone. As we find out more about the past and our ideas change, so we should be prepared to alter our interpretations of old discoveries.

Written by Keith Fitzpatrick-Matthews