Fresh from the Trench: Week 4

Light brown latch with a loop at one end and a very shallow hook resting in someone's cupped palms.

Right at the end of the day yesterday, one of our new students was working in the extended sondage near the trench entrance ramp. She found this iron object in the southwest corner of the mini-trench, abutting the edge of the cobbled yard in the southeast part of the trench. We think it looks like a latch, with a suspension loop at one end and a tapered, very shallow hook at the other end that might catch an “eye,” or loop/U-shape hammered into a surface. Even though it is corroded, it still retains the probable shape of the object rather well.

This isn’t always the case! Iron is particularly difficult to work with when it corrodes. Much of the iron we excavate are small objects completely covered in corrosion, sometimes identifiable as nails or tacks but other times just oblong lumps. On other sites, we have all seen iron concretions that reveal nothing of the original object until they are x-rayed! On another site, for example, something vaguely like a scotch egg appeared, and when x-rayed was shown to be multiple links of a chain that had rusted together. Iron corrosion is also very cheeky in that it often consumes or cements the iron object to nearby objects in the findspot, making them corrode as well. Think back to the image in our riddle solution post to see what iron and copper rivets look like corroded together: pretty unidentifiable at first glance. We have all seen iron corrosion pick up soil and sand, and sometimes even bits of bone and pottery!

How do we know it is iron? Many of the common metals we find archaeologically are fairly readily identifiable by their corrosion! Other clues like weight could be used but examining the corrosion allows you to simply observe particularly vulnerable metal objects without handling them. Iron commonly forms oxides, in an attempt to stabilize itself, and that’s how we end up with rust. Ferric oxide and ferrous oxide, brown and red/orange respectively, are what we find most often. Another metal that we have found on site frequently are copper alloys, which in our particular archaeological environment tend to turn green and pale green depending on the electrochemical changes; these colors represent the presence of chlorides rather than oxides. Lead, in addition to being much heavier than it looks, usually corrodes into carnbonates, giving it a white or grey appearance. Silver is most often affected by sulfur, leaving a black tarnish. And what about the shiniest-of-shinies? Gold doesn’t corrode hideously at all, it just becomes a purer form of itself!

Way Back Wednesday: Week 2

This Wednesday we have taken a fantastic iron arrowhead out of the archive to share because it looks very…shall we say…sharp. The pointy end is 5cm, while the other end is socketed, meaning it has a round opening that would be slid over a wooden shaft and secured with hide glue (a glue technology that goes back thousands of years involving stewing animal hides treated with lime).

BC04 SF1616 Before (2)

BC04 SF1616 Before (1)

Before conservation.

 

This medieval weapon would have likely been used for hunting rather than warfare, but in a pinch would certainly do the job if needed. Our arrowhead is slender with a triangular head and diamond or oval cross-section, suggesting it could have had multiple uses. Armour-piercing arrows from the medieval period, which we call bodkins, tend to be thin, squared and tapered to a point or even chisel tip, but without barbs; they are more successful against mail and plate armour than broadhead arrow points (large triangular heads with barbs) which themselves caused more damage to flesh. We can get an estimate of our arrowhead’s date simply by looking at the typology provided by Oliver Jessop’s 1996 typology which calls it a “multipurpose triangular arrowhead (MP1).” It is a bit longer than the example he provides, but we are relatively confident that that is just a minor variation of the same type. The London Museum’s earlier typology from the 1940 catalog call it a “type 2,” but they used a much narrower classification system. Unfortunately, these socketed arrowheads were in use a long time, from about the 11th to 15th centuries, so it is at this moment that we turn to our excavation record! We can look at the data from the context in which it was found, examining the context’s location in the trench and the other artefacts associated with said context. From our records, this arrowhead was found in a 13th-century occupation layer that may have been associated with a timber building.

BC04 SF1616 After (2)

BC04 SF1616 After (1)

After conservation.

Bamburgh Castle Early Medieval Metalwork Conservation: Iron Objects

As part of the Bamburgh Research Project’s (BRP) funding from the Society of Antiquaries of London (SOA) (learn more about the project here: SOA Funding Success), the BRP have been working with a conservator to identify metal objects that may require additional research and conservation to help preserve them and, in some instances, reveal new details about their form or decoration. The latter is particularly pertinent for iron objects, as corrosion often masks the finer detail of many objects.

SOA Logo

Funding from the SOA and Bamburgh Castle has enabled us to have all the early medieval metalwork from the castle conserved. We recently received the conservation report for all the iron objects. Below you can see some of the before and after images of key items from the assemblage.

Angled back Seax with fuller and whittle tang. Swirls indicative of pattern welding, seen in x-ray and during conservation.

 

Object BC08 6531 sf 3234 has been identified as a small C-shaped fire-striker of probably eighth to tenth-century date, but further research would be required to confirm this.

Each conserved item is returned to the BRP with before and after photographs and an individual conservation report, noting what work has been undertaken, any suggested further work required and how to best store the object(s) in long term storage. You can see an example of such a report here: Iron Fire-striker Conservation Record

Eventually, we aim to create a new museum display within the Castle, so visitors can see the conserved metalwork and learn how this material has added to our understanding of the sites development, particularly in the West Ward of the castle where we have discovered a 9th-10th century metalworking area.