The Modius Claytonenesis

By Pat Hirst, Volunteer

On a summer morning in June 1915, Mr M Reay, Greenhead village postman, was walking his usual round, probably thinking about the war or his impending retirement. He was used to the route, so possibly gave little thought to the archaeology beneath his feet, for his round included the remains of Magna Roman Fort on his way to Carvoran farmhouse.

He knew the west end of the field was boggy, but there were stepping stones to ease his passage. On this particular day, and for unknown reasons, he decided that one of these stepping stones was markedly different from the rest and began to investigate. The ‘stone’ was indeed different, for Mr Reay had found an extremely rare Roman modius, now called the Modius Claytonensis as a tribute to the estate then owned by the descendants of John Clayton.

This is a grain/liquid measure made of copper alloy and bearing a Latin inscription:

I M P [erasure] C A E S A R E



. – HABET . P . XXXiiiX

Expanded and completed, this would have read:

imperatore Domitiano Caesare

Augusto Germanico xv consule;

exactus ad sextarios xvii semis:

habet pondo xxxviii.

The English translation is as follows:

When Domitian Caesar Augustus Germanicus was consul for the fifteenth time, this measure was tested to the capacity of 17.5 sextarii: Its weight is 38 pounds’.

Carvoran Modius

Who was Domitian?

Domitian was a consul during the Roman republic. Although he had carried popularity with the soldiers of the Roman Army, having given them a large pay rise in 84 AD, he was not a popular man amongst the senate in Rome. By 96 AD, he was murdered by a group that included senior Praetorian Guards, palace officials and even the emperor’s own wife, Domitia Longina. The memory of him was ‘damnatio memoriae’, meaning all references to a person in written, engraved, sculptured or pictorial form was erased in the hope that he would be forgotten forever. We can see this on the Carvoran Modius.

What is a Modius?

Domitian ruled the Empire from 81-96AD, so we know the modius was made sometime between these dates, but not where it was made. The modius was a Roman measure of wheat or any dry or solid commodity, and sometimes liquids. It contained a third part of an amphora, and, in the first century AD, five of these measures of grain per month was the ordinary allowance given to every male adult citizen, with four allocated to slaves. Five modii per month is the equivalent of 3,000 to 3,500 calories per day for a single person, though often this was to be shared by whole families. It has been calculated that 2,000 soldiers would need 26 modii to supply their daily needs.

There are various mentions of modii in the Vindolanda writing tablets proving it was the official measurement of both wet and dry goods. Tablet 343 was found in a room in a barrack block from period four occupation of approximately 104-120AD. Tablet 302 mentions modii of fish sauce, 190 refers to Celtic beer, and 185 suggests that 1 modius cost 1 denarius. Inscriptions were not confined to writing tablets however: there are many inscriptions on amphora and other pottery wares, such as that in Wroxeter with ‘versuvini vini ii modii semis’ translated as 2.5 modii of Vesuvian wine. We can only wonder how delicious this tasted!

The mysteries of the Modius

The Modius Claytonensis holds more than other known modii found in Pompeii and Herculanium, and the Modius Mediceus now in the museum in Florence, which are recorded as holding 16 sextarii. All are cylindrical with the same internal bar and three-armed piece at the top. The Modius Claytonensis was obviously for dry goods because the bottom is not welded to the sides, nor is the base at the bottom of the vessel but slightly above it just as in a modern galvanised bucket. Interestingly, this modius holds more than 17.5 sextarii, which it claims in the inscription, and instead has a capacity of 20.8, so if it were used to pay compulsory taxes in the form of grain, as is commonly supposed, then the army was defrauding the tax payers. 17.5 sextarii was equivalent to16.8 pints, (1 sextarius equalled 546ml or approximately one pint). Since Roman measures were usually accurate, there may be missing attachments held by rivets, the holes of which are still present and could account for the discrepancy. Another reason for the discrepancy was postulated by JC Mann (article produced in Archeology Aeliana 5 vii) in which he says at first glance, it looks as though 17.5 is not divisible, but in fact can be divided by 7 – the number of days in a week (time to get the calculators out!), giving a 2.5 daily allowance of the contents. If indeed it were weekly grain rations, were the recipients being issued with a very generous over allowance far away from the rulers of Rome?

The Modius Claytonensis is on display at Chesters Roman Fort museum, now in the care of English Heritage.


I am indebted to the article reproduced in Archaelogia Aeliana from an original paper presented to the Society of Antiquaries of Newcastle upon Tyne by By Prof. F. Haverfield, LL.D., F.B.A., vice-president, and read on the 29th September, 1915.

Other references:

Archeology Aeliana 5 vii

English Heritage

Liversidge, 1968

Robert Rowland Jnr. (JSTOR)

‘The Daily Grind’, blog by Patricia Gilhespie

Roman Inscriptions in Britain, the British Museum

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