by Jamie Hood and Alexandra Baldwin, British Museum
With the Iron Age Chiseldon cauldrons excavated and cleaned to expose the metal surface the team at the British Museum are beginning to see interesting technological features and evidence of manufacture revealing them to be sophisticated and high status objects.
Tool marks on the surface from the original manufacture. © Trustees of the British Museum
Although the cauldrons are over 2,000 years old, different tool marks from shaping and thinning the copper alloy are still preserved and visible on the surface of the metal. These suggest the careful and deliberate use of specific tools for different tasks, indicating that the objects were made by a craft specialist skilled at working in sheet metal.
Faint incised lines marking out the position of rivets. © Trustees of the British Museum
Other features likely to relate to construction are the lines, faintly incised into the surface of the sheet copper-alloy and only visible in raking light. These appear to mark the overlap of plates making up the sections of the cauldron, and the regular distribution and position of rivets indicating that the cauldrons were carefully designed and made.
Examination is also showing that, while the 12 cauldrons are broadly similar in their design, there are variations in their size, shape and construction
Examination is also showing that, while the 12 cauldrons are broadly similar in their design, there are variations in their size, shape and construction. We have already identified three different types of rim construction. These differences are extremely intriguing and suggest that the cauldrons were made by different makers and/or at different times.
Multiple repair patches on the cauldron base. © Trustees of the British Museum
Another intriguing feature we are encountering is a high number of patched repairs. Some repairs appear to have been applied at the time of construction and placed over fatigue cracks caused by raising the metal. Others quite clearly cover areas of damage caused during the useful lifetime of the cauldrons, indicating that they were used and repaired over a period of time and were already old and well-loved items at the time of their burial.
Preserved details like this mean that while the cauldrons are in relatively poor condition there are minute pieces of evidence that allow us to build up a wider picture of how the cauldrons were designed and made, and really bring the objects to life by allowing us to see the craftsman’s thought process and the practical application of their art.
Source: (with kind permission) British Museum News
More information:
The Chiseldon cauldrons were discovered in 2004 by Peter Hyams, a metal detectorist. Initially it wasn’t clear what the objects were or how old they might be, so they were left in the ground until a local historical society could conduct a small excavation. This revealed a vessel made from copper-alloy and iron, as well as copper-alloy from a second vessel. Excavations found a minimum of 12 fragmentary Iron Age metal cauldrons deliberately buried together in a pit with two cow skulls. The cauldrons were stacked or placed in the pit whole and roughly half were upside down.
Conservation of the cauldrons from Chiseldon involves micro-excavation from its soil block in the conservation lab at the British Museum. The plaster bandages and clingfilm barrier layer used to support the fragile object during lifting and transport are gradually cut away. Soil is removed from around the object in layers using small dental tools and scalpels. Each stage of the process carefully recorded with photographs and drawings. The position of any detached fragments of metal or analytical sample was noted and then removed. The bowl of the first cauldron to be examined is formed of a single sheet of copper-alloy, less than one millimetre thick, hammered to shape.
- Unearthing and conserving an Iron Age feast From find to conservation
- Chiseldon cauldron Video The excavation and conservation of an Iron Age cauldron.