Troy Weight in Bronze Age Germany
This article appeared in Northern Earth, issue 124, Midwinter 2010-2011. It sets a rather amazing discovery reported by Prof Pare within an evolving understanding of Troy weight.
Robert Tye
In 1638 the Oxford mathematician John Greaves visited Egypt, in search of our earliest measures. Although no one seems to have noticed it, in 1999 it became clear that Greaves very likely had, unknowingly, found one of them.
Here I want to outline the story of that discovery. For those who wish to check the rather simple calculations, I lay them out in an appendix.
Greaves had figured out that the pyramids were the oldest buildings then known: based upon the available texts, he thought they were built around 1266 BC. His plan was to travel to Egypt and measure the pyramids, and deduce the very ancient standard of length used by their Egyptian builders. But my interest here is not in this but a different matter, his chance discovery that a system of weights, in use in Egypt in 1638, was astonishingly similar to the English troy system.
The troy pound comprises 12oz, each ounce (of c. 31.1gm) containing 20 pennyweights, each pennyweight containing 24 troy grains. It was officially specified in England for weighing gold, silver and bread. A mathematical derivative of it, sterling weight, was used to regulate medieval coinage. And a different derivative of it was employed in weighing drugs by apothecaries. These versions of troy are all to be distinguished from a different and more commonly used pound, called avoirdupois, used for weighing wool, meat and sundry other commodities. Avoirdupois gave rise directly to British Imperial and US customary pounds, and they have a different ounce, weighing almost 10% less than troy (c.28.35 gm).
According to the Oxford English Dictionary, the name troy, as applied to a weight, was first in use around 1390, and OED derives the name 'troy' from the French market town of Troyes. This dubious explanation neglects the rather vital fact that the weights used at Troyes do not appear to have been troy weights. In 1823 Gilbert offered a different derivation, getting the name ‘troy’ from Geoffrey of Monmouth’s Historia Regum Britanniae (c. 1136) (1). That is to say, he suggested that troy weight was the very first English standard, brought from Troy by Brutus after the Trojan war. It seems to me that Gilbert got the etymology right, the name of the standard is medieval, and derives from the assumption that the standard was one originally brought here from Troy. And I argue here that Gilbert was also on the right track concerning the standard itself, which is in fact much older even than the Trojan Wars.
Greaves made very little of this discovery on his return to England (2). However, George Hooper, Bishop of Bath and Wells, consulted Greaves’ work and saw its importance, publishing his results in 1721 (3). The resemblance of English and Egyptian weights was so great that he deduced, surely correctly, that English troy weight must have been acquired from the Arabs, and guessed that it had been brought back here by Edward I after the Crusades.
Studying ancient weight standards became a popular science in the early 18th century. Isaac Newton wrote a piece associated with Greaves’ findings, and John Arbuthnot, (inventor of the comic figure John Bull), wrote something of a bestseller popularising Hooper’s claim (4).
Strangely, however, the discovery that troy weight came from the Arabs seems to have been almost completely forgotten by 1840, and when Ruding wrote on the history of English weights (5) he made no mention of the idea. Ruding wanted to believe English weight came from the Anglo-Saxons, and used a more or less imaginary account of Anglo-Saxon coinage to try to justify that opinion. Thus, the Islamic origin of English troy weight seems to have been forgotten for more than two centuries. The maverick American economist Alexander del Mar rediscovered it in the late 19th century (6), but like almost all of Mar’s ideas, it was ignored at the time.
Thus, investigation of the matter was hardly seen again until 1967, when it was again taken up by F G Skinner, Deputy Director of the London Science Museum. He died before his work could be published, and what appeared was just a slim volume put together by his colleagues (7). In it, Skinner showed that the English troy and its derivative sterling weight systems were virtually identical to those adopted by Caliph Abd al-Malik in 699 AD. Since the sterling system seems to have been first clearly applied to English coin around 1083, it seems likely that this very exact form of 'troy' came to England with the Jews of Rouen, who accompanied William the Conqueror (8). Skinner went much further, however, detailing how in its original form troy comprised 16oz, equal to a Great Pound or Ratl Kabir, of c. 500gm. This Great Pound was the pound, or mina, of Darius, King of Persia (c. 550-486 BC) and much earlier yet by King Shulgi at Ur, 2,029–1,982 BC. Skinner also investigated the very earliest Egyptian weight, which he calls the beqa. He equated it to a binary multiple – 256 – of the wheat grain. The Ratl Kabir was equated to 40 beqa, thus to 10,240 wheat grains. In medieval England, 4 wheat grains by definition equalled 3 troy 'barley' grains; thus, 16 troy oz still contains exactly 10,240 wheat grains. Today it weighs 497.66 gm.
Strangely, Skinner’s re-discovery was forgotten even more quickly than Greaves’ discovery had been. A new HMSO account of English weight published by Connor in 1987 (9) made a cursory attempt to derive Troy from Roman standards in a complicated and unconvincing way. It ignored Skinner, Greaves and the Arab connection altogether, leaving matters prior to 1066 shrouded in mystery. In a further work in 2004, Connor retreated further (10), contradicting his own earlier work, and moving the origin of troy weight to the 14th century.
So at the time Skinner died, the English search for ancient origins for the troy standard apparently died with him. The strangest twist in this story comes because, at almost exactly this time, but overseas, archaeologists began to realise that some of the strange lead, marble and bronze items they were finding on European archaeological sites were weights. The earliest reports came from Petruso in the 1970s, concerning very early weights found in Crete and the Greek Peloponnese (11). Following on from this, in 1999 Pare reported prehistoric weights from Germany, and elsewhere in Central Europe (12) .
Pare was reporting weights excavated from German graves of about 1300 BC. He discovered within them fundamental standards of c. 12.2gm, c. 61gm and c. 488gm. Both Petruso and Pare seem happy to believe that these standards had spread from the Eastern Mediterranean into the Peloponnese, and thence into central Europe, over the period c. 2000-1300 BC. But neither acknowledged the two obvious further possibilities, that the antecedents of this system are to be found in very ancient Egypt and Persia, nor yet that it still survives today, in the English Troy ounce and pennyweight, and the Egyptian dirhem. But given the timescales involved, and the accuracy of prehistoric balances, 12.2gm looks quite a good fit for an Egyptian beqa of 256 wheat grains (and thus also 8 troy pennyweights, or 4 Egyptian bullion dirhems). 61gm is quite a good fit for two troy oz, and 488gm for the Ratl Kabir or great pound of 16 troy oz.
Perhaps the most astonishing item in Pare’s catalogue of finds is a bronze weight found in a grave at Wallerstädten, Hessen, Germany. It was made, probably in Germany, around 1300 BC, but buried with a Frankish warrior around 600 AD, that is 2,000 years later – evidence of a deep seated need to hold fast to the most ancient weight traditions. The piece is damaged, but Pare reconstructs its weight at c.6.44gm –not a bad estimate of 128 wheat grains, or half an Egyptian beqa (or two dirhems, or four troy pennyweights).
The story of the weights seem to be this: that what we today call 'the troy standard' arose out of Egyptian and Persian traditions going back 5,000 or more years. Versions of the system percolated into central Europe more than 3,000 years ago, and persisted there for more than 2,000 years, during which time they were surely brought to Britain by both Bronze Age and Anglo-Saxon visitors. Celtic coins and Anglo-Saxon weights both point to this conclusion. The Arabic system, apparently brought to England by William and the Jews of Rouen, also derived from the same ultimate system, that of very Ancient Egypt. It seems very possible that the Jews of Rouen recognised the fact that England was already using a rather rough and ready version of what we call the troy system, and so regularised it, using the very exact determinations of the standards created by Caliph Abd al Malik.
But our story of the troy weight standard does not have to stop with the story of the weights, if we are willing to push on with speculation. The central principle of troy weight seems to be the very ancient pound of around 500gm, or 16 troy oz. Called the Great Pound (Ratl Kabir) in the early Arab empire, Skinner used stone weights to trace this standard back more than 4,000 years in Persia, more than 5,000 years in Egypt. But the idea of weight must come before the first weight was made, and so we can speculate too about the idea which gave rise to a c. 500g standard. For if you cup your hands you will have the earliest measure available to man, and if you scoop up a heap of grain in them, you will probably find that you are holding c. 250g of grain. Two such measures will make a Great Pound, or mina, which is around the amount of grain needed to feed a person for a day. And mina means a unit of count. Thus we can at least speculate that the original troy pound, of c. 500g, goes back to the very first grain harvests, when the corn was being measured, divided and stored by the very first farmers.
A final mystery remains concerning our ancient English standards. Bronze Age people here must surely have used weights, but it is possible they were just bags of selected pebbles. So far archaeologists have failed to find them. Or maybe they have found them, but have not realised what they are?
Appendix
An English troy pound is 12 troy ounces of 20 troy pennyweights of 24 troy grains = 5,760 grains each of 0.064799gm, thus 373.24gm. The Egyptian monetary pound was divided in exactly the same way as troy, except 48 grains made the dirhem, and 10 dirhems the ounce (that is to say, the penny is a half dirhem)...
Greaves found the Egyptian bullion dirhem to be 47.82 grains (1647), yielding an Egyptian pound that differs by only 0.4% from troy.
.Additionally, just as the troy pennyweight can be divided into 24 troy grains or 32 wheat grains, the Egyptian dirhem was divided into both 48 barley grains or 64 wheat grains.
Also, when medieval sterling pennies were produced, their weight was 1/16th less than troy, that is 30 wheat grains, thus 1.458gm. Texts tell us the coin dirhem of Abd al-Malik in 699 CAD weighed 60 grains, and from the coins we find that to be 2.92gm – 99.8% of the troy sterling standard at that earlier time.
Today, 16oz troy is 497.66gm. The Arab 7th-century great pound seems to have been c. 498.4gm. The pound of Darius (c. 500 BC) was 500.19gm, the pound of Shulgi (c. 2000 BC) 504gm. This pound, as it spread into Bronze Age Europe, seems to have lost a little, becoming c. 488gm. But that would lead to a rather trivial difference in the weight of the apothecaries' drachm, used then and now, which is 1/128th of the pound. Today that is 3.89gm, in Bronze Age Europe it would average 3.81gm.
Note also that scales in 2000 BC would probably not distinguish 490gm from 500gm at all; thus, the further we go back, the more we must rely on the averages of the known weights.
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1. R D Connor, Weights and Measures of England, 1987, HMSO, , pp118-9
2. John Greaves, A Discourse on the Roman Foot and Denarius, 1647, p.115
http://tinyurl.com/35f5z2z
3. The Works of the Right Rev. George Hooper, Bishop of Bath and Wells, 1757, Vol. 2, p.11
http://tinyurl.com/3y84sg6
4. John Arbuthnot, Table of Ancient Coins, Weights and Measures, 1727, p.54
http://tinyurl.com/32eyqh3
5. Roger Ruding, Annals of the Coinage of Britain and its dependencies; London, 1819, p.6
6. Alexander del Mar, A History of Monetary systems, London, 1895, p.185
7. F G Skinner, Weights and Measures, HMSO, 1967
8. Robert Tye, Early World Coins & Early Weight Standards, York, 2009, p.137
9. See 1 above
10. Connor & Simpson, Weights and Measures in Scotland: A European Perspective 2004, HMSO
11. K M Petruso, Keos, Vol. VIII. Ayia Irini: The Balance Weights, Mainz am Rhein, 1992,
12. C Pare, , Weights and Weighing in Bronze Age Central Europe in Eliten in der Bronzezeit,
