Some wet day speculation, or how to read a little too much into some burning

It’s probably only fair to start this blog with a warning that in places it contains more than a little speculation! Hopefully I will make the areas where I am reaching a little, apparent in the text.

This last week, within Trench 1 at the castle, we have been removing the last fill from our middle Saxon timber hall. This structure is clearly traced, cut through boulder clay subsoil, and also in places, through the bedrock. So we have, quite literally, hard evidence for the footprint of this building. Its height is less certain, but even if it was a fairly normal single storey structure, its position immediately above the cleft in the rock that leads down to St Oswald’s Gate, would mean that it would tower above anyone entering the fortress. Our best interpretation for it function is as the gate wardens hall. This is based on its location and impressive siting, so represents our first bit of speculation. To its immediate west and very close to the edge of the bedrock, where it falls away to the external ground surface (outside the castle), a heavily constructed rubble foundation extends, parallel to the bedrock edge. We identified this several years ago and have described it ever since as the foundation for the inner wall of a box rampart. Part of a timber phase of the fortress’ defences. We believe this to be early medieval, though can only date it to before the 12th century AD, with any certainty.

So far we have looked at the archaeological evidence and have made some quite reasonable extrapolations from the structures and material that we have unearthed. During the last few days we have identified some patches of discoloured subsoil that are almost certainly the result of some pretty intense burning. Intense enough to penetrate to the subsoil and chemically alter it. This burning lies in the narrow gap between the foundation for the wall of the building the gate cleft. One possible explanation for this would be that the workmen, who cut the bedrock for the building foundations, used a technique of heating and rapid cooling with water, to fracture the bedrock. This does not seem to be likely though as we have identified a number of examples of foundations cut through the bedrock and do not see this elsewhere.

The corner of our construction slot for the timber building as it approaches the rock cleft at St Oswald's Gate

The corner of our construction slot for the timber building, as it approaches the rock cleft at St Oswald’s Gate

The discouloured subsoil is easier to see with the naked eye, but perhaps is just discernable.

The discoloured subsoil is easier to see with the naked eye, but perhaps is just discernible.

This leaves us with another exciting possibility. The burning is very close to the gate, and our inner line of timber defensive wall, which raises the intriguing possibility that this represents an attempt, by an enemy force, to burn their way into fortress through its most vulnerable point. In fact we have a record, in the pages of Bede, to just such an event at Bamburgh in the later 7th century, when Penda, King of Mercia, made a great heap of timber against Bamburgh’s timber wall and set it on fire. In Bede’s story he goes on to relate how the prayers of St Aidan caused the wind to change direction and blow the fire and smoke back in the direction of the attackers, foiling their plans. Could we have evidence of this very attack, burned into the subsoil at the fortress’ weakest and most vulnerable point? Its certainly not impossible, but our speculation metre may now be close to off the scale, so we should perhaps leave it there. After all there are lots of reason why things catch fire and burn.