Forbury Mound – a final mystery solved

Our final site on the Round Mounds Project was right on our doorstep – the mound in Forbury Gardens, Reading.

As discussed in a previous post, Forbury Mound is something of an enigma. The fact was, no one really knew for sure what this strange broad-bean shaped low mound of earth was. Was it a monument to a slain Viking warrior, a castle motte hastily constructed during a period of civil war in the 12th century, or was it the mutilated remains of a 17th century gun emplacement?

The origins of Forbury Mound  remained mystery until this summer, when in June the Round Mounds team came to investigate.

As with the previous 19 sites, we aimed to date the construction of Forbury Mound by collecting core samples through the mound…

Dr Jim Leary with the equipment used to extract the core samples

In this way, we sampled just over 3m worth of archaeological deposits which comprise the mound, drilling boreholes in two locations – one in the middle of the mound, the other a few metres to the north. In the laboratory, the cores were examined, and small samples of sediment were taken from the cores to look for material suitable for dating.

Whilst for most of our sites we have relied on AMS (Accelerator mass spectrometry) radiocarbon dating to reveal the date of construction, Forbury Mound was rather more forthcoming with its secrets…

The core samples from Forbury Mound were full of archaeological material – detritus from every day life in the past. In particular the core samples were full of what archaeologists call CBM – ceramic building material – otherwise known to non-archaeological folk as good old fashioned brick and tile.

Fragments of ceramic building material (what archaeologists call “CBM”- brick and tile to everyone else…) and a fragment of oyster shell (top left) found in the core samples from Forbury Mound.

So why was the presence of brick/tile in the core samples from Forbury so revealing? Firstly, the presence of this type of tile means that the mound almost certainly cannot be any earlier than the 13th or 14th century – ruling out the possibility that the mound was a Norman castle motte, or indeed any other kind of earlier monument. Furthermore, the abundance of tile in the cores from Forbury suggests that the mound was at least partly made up of demolition rubble, probably following the demolition of a nearby building. And where could this rubble have come from? Just next door to Forbury Gardens, the ruins of Reading Abbey, disestablished in the 16th century, or one of its associated structures look to be the most likely source of this rubble.

Taken together, this evidence seems to support the one remaining hypothesis for the origin of Forbury Mound: that the earthwork is a remnant of Reading’s 17th century Civil War defenses. Indeed, this is what the mound seems to resemble in one of the earliest accurate maps of Reading produced in 1802. In this plan, shown below, the earthwork which is clearly labelled “Forbery Hill” has an angular form typical of civil war defenses, and part of the southern extension appears to overlie the site of Reading Abbey.

Detail from 1802 map of Reading by Tomkins, showing Forbury Mound (marked as “Forbery Hill”) which here looks much like the remains of a Civil War era defensive earthwork.

So there it is – it seems the mystery is solved. The last mound cored on the project has also turned out to be the latest.

As a final thought, it is worth noting that although the coring evidence points to a Civil War date for Forbury Mound, this doesn’t necessarily mean that there wasn’t a medieval motte on or near the site, just that if there was, the physical traces of any earlier activity have been erased by the later use of the site…