Simon Rostron

By Simon Rostron
LBMA Consultant

Town of Troyes

The concept of troy weight, although not the name, begins with cereals. The early Egyptian silver dirhem weighed 48 barley grains (and continued to do so for many centuries) and in the reforms to the English currency introduced by the Mercian King Offa (757-796 AD), matching those of Charlemagne, one silver penny weighed exactly half a dirhem. Indeed, some circulating coins of Offa’s time have been found to have been dirhems used either directly or partially restruck.

Despite the fact that the later medieval English system worked with wheat grains rather than barley grains (at a ratio of 4:3), today’s troy ounce weighs 20 pennyweights or 480 grains, and as Charlemagne decreed, there are still 12 troy ounces to the pound.

But whereas the name dirhem is etymologically connected to the Greek drachma, the origin of the name ‘troy’ is more difficult to define – the one certainty is that it has nothing to do with Homer!

There are several competing theories. The best supported of these links ‘troy’ to Troyes, the market town a little more than 100 miles south-east of Paris.


Troyes has a long and often colourful history stretching back to around 600BCE as evidenced by Celtic burial mounds nearby. Julius Caesar was responsible for the city’s original ramparts, fragments of which still exist, and in the later Roman period, these fortifications were certainly of practical value as the Emperor Julian discovered in 357 AD, when journeying from Auxerre (some 50 miles to the south-west) to Troyes to deal with an outbreak of lawlessness:

“So, as he now had firmer hope of success in resisting their attacks, he proceeded among many dangers to Tricasa [Troyes], reaching there so unlooked for, that when he was almost knocking at the gates, the fear of the widespread bands of savages was such, that entrance to the city was vouchsafed only after anxious debate.” (Ammianus Marcellinus – contemporary account, ToposText).

The Roman name for Troyes – Tricasa or, more fully, Augustobonum Tricassium – reflected the fact that it was the principal city of the Gallic tribe, the Tricasses. Some authorities, for example, the writers of Encyclopedia Britannica, have implied that ‘Troyes’ is a straightforward corruption of this name, but if so, this derivation poses a problem when the concept of troy weight is investigated, for what are we to make of the contemporary ‘Bremen troy’ and/or the ‘Holland troy’?

By the eighteenth century, as this plate for the Trial of the Pyx - the annual test of British Currency - shows, the Troy Pound had been long-established. The first definitive reference appears in a 1414 statute from the reign of Henry V pertaining to silver although it is likely this formal English measure dated back at least a further 140 years. (By permission of the Royal Mint).

The Champagne Fairs

As much as Troyes’ fortifications provided it with strategic importance, it was the city’s location at the intersection of a series of Roman roads, notably the direct route from Boulogne to Milan and another to the port city of Harfleur (a few miles inland from Le Havre), that led to its commercial heyday in the Middle Ages.

In short, Troyes became the capital of Champagne and one of four cities or towns which, under the rule of the Counts of Champagne, played host to ‘Champagne Fairs’, which reached their zenith in the 12th and 13th centuries. Although not as exciting as they sound to modern ears (given the manufacture of Champagne – in bottles – did not begin until late into the 17th century), these fairs were internationally important, serving as “a premier market for textiles, leather, fur, and spices” (Wikipedia).

The key question is whether the fairs at Troyes were better known and respected than those of the nearby cities such as Provins, 44 miles to the north-west or Lagny-sur-Marne, in the outskirts of modern Paris.

The answer is probably yes, given that Troyes hosted two fairs a year – one in June, the other in November. Therefore, so the argument goes, it was the system of weights and measures in force at Troyes that became institutionalised. But then again, Provins also hosted two Champagne Fairs every year.


Book Marks

This point in the narrative requires the introduction of three new characters: Henry, Henry and Watson. But before their relevance to troy weight is explained, a brief diversion into the world of the medieval ‘mark’ is necessary.

Like the pound, the mark was originally a unit of weight –almost always of precious metals – which at the outset was also an equivalent value. However, again like the pound, its weight and value diverged very considerably over the years.

Although familiar in England, the mark was never an actual unit of currency there so much as a unit of account. However, in Europe, more frequently in the Germanic and Scandinavian regions, there were many marks of differing value. That said, in the context of Troyes, it is or was the weight of the mark, which was often but not always equivalent to eight ounces, that is consequential.

Enter the first Henry: Henry Bolingbroke, Earl of Derby and latterly King Henry IV. It is to Henry, or more accurately to the book Expeditions to Prussia and the Holy Land made by Henry Earl of Derby in the years 1390-1 and 1392-3 (edited by Lucy Toulmin Smith, Camden Society, 1894) that we owe the first formal reference to troy weight.

In this book, written in curious medieval Latin with French and English inclusions, Henry’s Treasurer, Richard de Kyngeston, Archdeacon of Hereford, lists all the expenses that Henry’s military excursions incurred. In the section titled ‘Vasa Argentea’, dated January 7 [1390] and referring to silverware, is the following phrase [my numerals]:

Et pro 1 chargeour, 3 discis, et 1 sawcere, ponderis 20 marc. de troye, 45 marc.

In my loose translation, this says: “And for one charger, three ‘discs’ (presumably flat plates) and one platter weighing 20 marks troy [with a value of] 45 [English] marks.”

Most authorities consider the use of the term ‘de troye’ in this fragment to refer to weight.

But does this mean that the ‘troye’ referred to is synonymous with Troyes?

The First Act

Of course, it is possible that Henry or indeed Richard de Kyngeston had visited Troyes, particularly given the English stronghold of Calais (referred to in the book as ‘Calys’), which made the first step of any journey to Troyes much easier, but it is certain that the next reign saw a greater association with Troyes, and formally with troy weight.

Henry V’s brief military career is too well known to be recounted here, but in the context of this story, the important date is the year before Agincourt, when the first reference to troy weight as a formal and approved measure appeared in an English statute.

To quote Charles Watson, who will be more formally introduced below:

“In the second year of King Henry V, AD 1414, an Act was passed dealing with the price which was to be paid for articles of silver gilt. In this it is stated that the goldsmiths were in the habit of charging for silver-gilt ware double the price for pure silver, ‘which was an outrageous price’, and apparently, even then, the silver was not always of good quality. It was therefore enacted that in future no silver of less value than sterling (i.e. the silver used for coins) should be gilt, and that a troy pound of silver gilt-ware should be sold for £2 6s 8d [560 pence] at the most.

“This is the first time that the pound used for weighing silver, i.e. the pound of 12 ounces, is definitely called a troy pound in the laws of England …”
(British Weights and Measures, John Murray, 1910).

A related date is 1420, when following the Treaty of Troyes, Henry married the French King Charles VI’s daughter, Catherine de Valois, in the Eglise St-Jean-au Marché (in Troyes, of course) and became heir to France. Sadly (from the point of view of the English), Henry pre-deceased Charles, and following Joan of Arc’s uprising, that was that.

Eglise St-Jean-au Marché