Steelyard Weights

Introduction

The balance known as a steelyard required weights that could be suspended.  This was achieved either by hanging weights using integral or separately added loops, or by perforating a weight centrally to take a separate wire bent into a loop.  Weights used on steelyards were fundamentally made of lead; this was encased as a core in a copper-alloy casing sometimes in the Roman period, and generally in the medieval period.  Most steelyard weights recorded by the PAS are restricted to these periods, as these were the main periods of use of the steelyard as a weighing instrument.

PAS object type to be used

Use STEELYARD WEIGHT

Date

Steelyards weights recorded by the PAS are mostly either Roman or medieval.  The classic Roman steelyard weight is biconical and made of lead.  Some Roman steelyard weights have a lead core within a figural copper-alloy casing with an integral loop.  Medieval steelyard weights also have a copper-alloy casing and a lead core; these are broadly globular with an integral perforated lug and are often decorated with heraldic shields.  Currently these are all thought to date between c. 1250 (or slightly earlier) and c. 1350, the latter date firmer as the use of the steelyard was forbidden in 1350 (Cherry in Saunders and Saunders ed. 1991, 47).

Roman steelyard weights

The most common Roman steelyard weights are biconical, with a separate iron loop attached at one or both apexes.  If there are two loops, one is for suspension and the other holds a hook on which to hang the item(s) being weighed (Brailsford 1964, 78; fig. 40, no. 11).  An alternative to this construction was to perforate a biconical weight at its centre and insert a wire bent into a loop at each end; such weights are far less diagnostic found by themselves.  A separate group has a lead core within a copper-alloy casing which can take anthropomorphic or natural forms.  The former often take the form of Roman deities or their attendants.  They can be distinguished from figurines or furniture mounts by a combination of the presence of lead internally, and evidence of a loop.  The mass of a steelyard weight must be included in the record, and can be compared with the Roman weight system, detailed in the guide to steelyards.

Roman steelyard weights: Biconical with two iron loops (left, WILT-209BB6); Biconical with central hole, detail from from steelyard (centre, WMID-184456); Anthropomorphic copper-alloy cased (right, HAMP-079895). Copyright: Salisbury and South Wiltshire Museum; Birmingham Museums Trust; Winchester Museum Service; CC-BY licence)
Roman steelyard weights: Biconical with two iron loops (left, WILT-209BB6); Biconical with central hole, detail from steelyard (centre, WMID-184456); Anthropomorphic copper-alloy cased (right, HAMP-079895). Copyright: Salisbury and South Wiltshire Museum; Birmingham Museums Trust; Winchester Museum Service; CC-BY licence)

Medieval steelyard weights

The main group of medieval steelyard weights are broadly globular with a flattened top, at the centre of which is a thinned triangular projecting lug which is perforated for suspension.  At the top of the main body of the weight there is often an engraved double line border which may contain triangles.  Around the centre of the weight are either three or four shields cast in low relief.  Towards the base of the weight there may be evidence of a hole from the lost-wax casting of the object; this was to extract the wax and fill the weight with lead (Ward Perkins 1967 (1940), 172).

Medieval steelyard weights: official weight with band of triangles above the shields (left); unofficial weight with unusual shield, and simple ridges and grooves above (centre); plain weight (right). Copyright: Suffolk County Council Archaeology Service; The Portable Antiquities Scheme; Somerset County Council; CC-BY licence)
Medieval steelyard weights: official weight with band of triangles above the shields (left); unofficial weight with unusual shield, and simple ridges and grooves above (centre); plain weight (right). Copyright: Suffolk County Council Archaeology Service; The Portable Antiquities Scheme; Somerset County Council; CC-BY licence)

The decorative shields were charged with heraldic devices which allow for dating of these objects.  Two main groups have been discerned by stylistic analysis (Drury Classes I and II) or by metallurgical analysis (Brownsword and Pitt Types A and B): more details can be found in Cherry (in Saunders and Saunders ed. 1991, 47), and by following up the original works in its bibliography.  It has been noted that one group of these weights (Class A) always features a combination of particular arms, those of Richard, Earl of Cornwall and Poitou, or Edmund, the second Earl, his son (Ward Perkins 1967 (1940), 172).  Certain of these arms can also be found on a distinctive type of bell:

  • a double-headed eagle: Richard was elected King of the Romans (Germans) in 1257; this was the symbol of the Holy Roman Empire, and also of the Hanseatic merchants.  Weights bearing this device must date at or after this event in 1257.
  • a lion rampant: for the county of Poitou.
  • a lion rampant surrounded by a border of bezants: for the earldom of Cornwall (in particular, the border).
  • three lions (leopards) passant: for England.
  • three chevrons: for the Clare family.  Edmund married Margaret de Clare in 1272.  Weights bearing this device must date at or after this event in 1272.
Shields of arms on medieval steelyard weights of Class A: double-headed eagle (left); lion rampant (centre); three chevrons (de Clares, right). Copyright: various; CC-BY licence)
Shields of arms on medieval steelyard weights of Type A: double-headed eagle (left); lion rampant (centre); three chevrons (de Clares, right). Copyright: various; CC-BY licence)

Given the consistent employment of these arms, a consistent high-zinc alloy (Brownsword and Pitt 1983), and other common features such as the band of engraved triangles above the shields, it has been argued that this group were officially produced weights, the centralised production of which the successive Earls of Cornwall had a monopoly (Cherry in Saunders and Saunders ed. 1991, 47).  It is thought that they began in c. 1250, with later start dates that can be entered given the presence of a double-headed eagle (1257), or three chevrons (1272).  Cherry (in Saunders and Saunders ed. 1991, 47) suggested that this official production ceased in around 1300.

Other weights in a ‘leaded bronze’ (Type B) can be distinguished by the inclusion of shields that deviated in some way from the above group.  These are regarded as copies of the standard issue weights, produced later: from the end of the 13th century or the first half of the 14th century, the use of the steelyard being forbidden in 1350 (Cherry in Saunders and Saunders ed. 1991, 47).

Certain of the above weights tend more towards a drop shape, and have less finely engraved detailing above the shields (e.g. Ward Perkins 1967 (1940), pl. XXXVIII, no. 1).  On one example the arms are engraved (Drury Class II); above, the engraved lines are thick, creating ribs.  This object helps connect the more common above globular group of steelyard weights to a group of drop-shaped weights which tend to have a plain copper-alloy casing.  Despite such weights having been published as possibly Roman by Read (2016, 121; nos 834-836), based on finds in the vicinity, an example is known from Castell-y-Bere which was built in 1221 (Butler 1974, 92; fig. 6, no. 1).  On the basis of the connections with the main group, a date range of c. 1250-1350 can also be suggested for these weights, although an earlier start date cannot be ruled out on current evidence.

Examples

Search for all examples of steelyard weights

Key references

Cherry in Saunders and Saunders ed. 1991

Ward Perkins 1967 (1940)