BROOCH

TREASURE CASE 2017 T1032. NOT TREASURE. Description: An almost-complete heavily silvered and gilded copper-alloy disc brooch of Anglo-Saxon date. The brooch has a wide plain rim within which is the decorative field. Four flat-topped circular bosses, each with thick silvering or an applied sheet of very thin silver, are set around the central quatrefoil, which consists of four U-shaped cells around a central circular cell. Each of the four U-shaped cells curves very slightly in the same clockwise direction, giving the effect of a clockwise movement to the motif. There is no trace of the type(s) of insert that would have filled these cells, but they may have been garnet or glass which are both commonly seen on brooches of this period. The cell walls are cast in one with the rest of the brooch and have thick gilding on their sides, which has worn off the top of the cell walls. There is no obvious foil surviving at the bottom of any cell, although some are still full of soil.

Surrounding the central motif and interrupted by the curved outer tips of the U-shaped cells is a ridge with stamped dots (or possibly tiny annulets) along the centre, giving a beaded effect. Outside this border are four panels of relief decoration, divided by the four bosses. Each panel appears to be different and may be zoomorphic, but details are hard to see and the designs may be an abstract form of Salin's Style II. The ridges are all emphasised by the same stamped dots or tiny annulets. Another ridged, stamped border surrounds the outside of this field of decoration. The whole of this central area, apart from the bosses, has been gilded and much of this still survives.

Outside the zone of relief decoration is a wide flat border, which is a silvery colour, and may originally have been silvered or tinned (but see the XRF analysis of the reverse, which is a similarly silvery colour).

The reverse of the brooch retains the double lug for the insertion of the pin, which from the corrosion adhering to lugs appears to have been of iron, although the pin is now missing. Opposite the lugs is the remains of the catchplate. An second area of iron corrosion adheres to the reverse a centimetre from the catch - this may be the remains of the point of the pin. The reverse of the brooch is silver in colour, which initially suggested that the brooch was made from debased silver rather than silvered and gilded copper alloy, but analysis found the latter to be correct (below)

Discussion: Jo Ahmet (Finds Liaison Officer for Kent), comments: 'This brooch is interesting...the panel[s] of fairly well defined Style II animal motifs would put this with Avent's Keystone Garnet Class 7. It must be noted that Class 7 is far more loosely grouped compared to earlier classes...and are only really linked by the clearer Style II motifs. Much of Avent's work is based on cemetery finds, admittedly disturbed but considering the drop in grave goods from the last quarter of the 6th century it is not surprising these later dated brooches are a bit vaguer. I think Avent's original dating of of [AD] 575-630 is still reasonable. I think this could roughly be grouped with Class 7.4 on the basis of a series of limbs connected with a fairly simplified ribbon-like body; incidentally those brooches of Class 7.4 also have wide plain outer rims. [However, this brooch] does have an additional setting and boss, so [the exact comparisons are a] bit tenuous.

Coroner's report 1st August 2018:

An incomplete cast metal disc brooch from the early medieval period. Non-destructive X-ray fluorescence (XRF) analysis of the surface metal on the back of the brooch identified the metal of the main body of the brooch as an alloy of copper and tin, with some lead and trace levels of other elements. The brooch has a wide plain rim surrounding a central decorative field, comprising four panels divided by four raised flat bosses, surrounding a cruciform arrangement of cells. Each of the four panels contains cast interlace motifs embellished with dots perhaps intended to give the appearance of beaded wire. Around the outer edge of the decorative panel is a raised circular border executed in the same manner. The four flat bosses are plain, with one (top right in photo) topped with an applied disc of sheet metal identified by XRF analysis as an alloy containing significantly more than 10% of silver, with some copper and trace levels of other elements. The cruciform cellwork comprises four curved arms around a central circular cell. All of the cells are now empty. The surface of the central decorative field is gilded. XRF analysis identified the presence of mercury, suggesting that the fire- or mercury-gilding technique had been used.

The reverse of the brooch retains a double lug for insertion of a now-missing pin, which from the corrosion adhering to lugs appears to have been of iron. Opposite the lugs are the remains of the pin's catchplate. A second area of iron corrosion is visible approximately a centimetre from the catch, perhaps the remains of the pin's tip.

Dimensions:
Thickness: 4 mm
Weight: 24.8 g
Diameter: 43.8 mm

Discussion:
This brooch belongs to the type of inlaid disc brooches categorised by Avent (1975) and traditionally associated with southern England, especially Kent - although metal-detected finds have helped to expand their distribution in recent years. The Leafield brooch does not sit perfectly within any of Avent's categories, and thus should probably be grouped into his Class 7, 'Uncategorised'. These brooches are dated to between the sixth and seventh centuries, but the style of ornament on this brooch suggests a date towards the latter part of this range.

Date:
Seventh century

Conclusion:
The precious metal portion of this object can be defined as a surface treatment, designed to be integral to the whole artefact rather than a distinct component. Accordingly, the precious metal component would need to make up at least 10% of the artefact for it to qualify as Treasure under the terms of the 1996 Treasure Act. In this case, it is unlikely that the precious metal component makes up 10% of the entire brooch and therefore it is suggested, for the Coroner's approval, that it does not constitute Treasure.

With thanks to Duncan Hook (Scientist, British Museum), Ian Richardson (Treasure Registrar, British Museum) and Jo Ahmet (FLO, Kent) for their contributions to this report.

References:
Avent, R., 1975. Anglo-Saxon Garnet Inlaid Disc and Composite Brooches. British Archaeological Reports, British Series No. 11

Authors:
Anni Byard
Finds Liaison Officer
Portable Antiquities Scheme

Dr. Sue Brunning
Curator, European Early Medieval Collections
Department of Britain, Europe and Prehistory
The British Museum