Tower pound

In England, 8ᵗʰ century? – 1527,, a unit of mass, about 349.9 grams. It takes its name from the Tower of London, which for many centuries was the location of the Mint. The principal use of the Tower pound appears to have been in regulating coinage. (It was also called the moneyer's pound.)

Henry VIII abolished the Tower pound in 1527:

Nowe yt is determyned by the Kingis Highnes and his said Councelle [that the aforesaid pounde Towere shall be no more used and occupied] but all manner of golde and sylver shall be wayed by the Pounde Troye which maketh XII oz. Troy which exceedith in the Pounde Towre in weight III quarters of the oz.

No standards are known to have survived. A bell-shaped brass weight found in the Chamber of the Pyx in Westminster Abbey in 1842 was found to weigh 5395 medieval grains, which strongly suggests that it was a standard for the tower pound. By 1873 this weight had disappeared.¹

1. Connor and Simpson, page 116, quoting from H. W. Chisholm, Seventh Annual Report of the Warden for the Standards..for 1872-73 (London, 1873), quoting from 1864 House of Commons Paper #115.

Subdivisions of tower weight

The Tower mark is the same magnitude as the mark of Cologne, and the Tower ounce is the same as the ounce of the mark of Cologne.


tower pound


tower mark


tower ounce









tower grain






tower mite






in grams

2.28 mg

45.6 mg





in troy grains







John H. Munro.
The Maze of Medieval Mint Metrology in Flanders, France and England: Determining the Weight of the Marc de Troyes and the Tower Pound from the Economics of Counterfeiting, 1388-1469.
Working Paper number UT-ECIPA-MUNRO5-98-01.
Available on the web at

Origins of tower weight and its role at the Mint

The Tower pound is sometimes described as the oldest English unit of mass. If that is so, it is only the concept of a unit equal to the mass of 240 pennies that is ancient, and not the 5400 grain magnitude. Although in the two centuries after 1080 the mass of the penny was kept at 22.5 grains, in the centuries before that the weight of the penny varied with each issue, from more than 27 grains (the “long cross” pennies of Æthelred II) to as little as 16.5, and a standard weighing 5400 grains would therefore have been of little use to a mint master.

In the two centuries after 1080 the mass of the penny was kept at 22.5 grains, and from the 8ᵗʰ century(?) to 1971 there were 240 pennies in a (monetary) pound. The Tower pound is equal to the mass of 240 pennies, each of 22.5 grains. Thus comparing a heap of 240 pennies with a Tower pound standard in a balance would reveal whether the pennies contained too much or too little metal.

The Tower ounce is another story, since ounces of 450 grains occur on the Continent.

The Tower pound was not employed in the elaborate trials of the coinage at the Exchequer, which were conducted in Troy weight.

Troy weight at the mint

Merchants bringing precious metal to the mint to be coined would have acquired it overseas, where it would have been measured in troy weight. For a troy pound of silver they delivered they would receive a tower pound of coins. The troy pound was heavier than the tower pound, and the difference went to the King.

In 1526 or 1527 Henry VIII replaced this way of charging for coinage by a flat fee system: 2 shillings, 9 pence for converting a troy pound of gold into the coins called “George nobles or half nobles”, 3 shillings for making it into “crowns of the double rose or the half thereof.”. The new system eliminated the role of the tower pound.

Was Tower weight used in commerce?

From Pegolotti (see source 1) we learn that in the 14ᵗʰ century the tower mark, not the tower pound, was employed in London in trade in silver as raw metal (sheet, ingots, and so on), but apparently in every transaction the Mint had to be either the buyer or seller. In Europe, its equivalent, the mark of Cologne, was in use since 1524 for precious metals.

Was the Tower pound the “Saxon pound”?

It is sometimes claimed that the tower pound was the pre-conquest Saxon pound. One must first ask what is meant by “Saxon pound”. On the face of it, it would seem to mean a unit of mass in the Saxon kingdoms of southeast England, or perhaps in Old Saxony. Unfortunately, little is known about their weights. As Krause wrote:

The issue of Anglo-Saxon metrological systems is extremely complicated, fraught with circular arguments, dubious assumptions, and cultural and temporal leaps.

Susan E. Krause.
Late Saxon Balances and Weights.
Medieval Archeology, vol 36, 1992.



In Londra si ha 2 maniere di pesare argento, cioè il marco della Zecca della Torre di Londra, che è appunto col marco di Cologna della Magna, e l'altro si è appunto col marco degli Orfevori, cioè degli Orafi di Londra, che è più forte, e più grander marco, che quello della torre sterlini 5. e un terzo di sterlini 20 per 1. oncia, e d'once 8 per 1. marco.

Al marco della Torre di Londra si vende, e compera tutte maniere d'argenti in piatte, o in verghe, o in monete, o in buglione per disfare, e nullo uomo, nè cittadino, nè forestiere non osa tenere cambio per cambiare in Londra altri che 'l maestro della Zecca della Torre di Londra.

A marco degli Orfevori si vende, e compera tutte vasella, è cose d'argento, che l'uomo avesse a trafficare con gli Orfevori.

In London you have 2 ways to weigh silver, that is the mark of the Mint of the Tower of London, which is exactly equal to the large mark of Cologne, and the other is precisely the mark of its Orfevori, i.e. the Goldsmiths of London, which is bigger, and larger than that of the tower by 5 and a third sterlings, at 20 sterlings to the ounce and 8 ounces to the mark.

By the mark of the Tower of London one sells and buys all manner of silver in sheets, or ingots, or coins, or bullion to be fashioned, and no man, neither citizen nor foreigner, dare keep an exchange in London other than the Master of the Mint of the Tower of London.

By the goldsmith's mark one sells vessels, and all silver items that concern the business of the goldsmiths.

Pegolotti (about 1340) Pages 259-260.


There hath been used from the beginning (in the Mint) both Troy and Tower weight, each of them containing twelve ounces in the pound weight, saving that the Troy weight is heavier by sixteen pennie weight upon the pound weight : by which Troy weight the merchants bought their gold and silver abroad, and by the same did deliver it to the Kings mint, receiving in counterpeaze but tower weight for Troy, which was the Princes Prerogative, gayning thereby full three quarters of an ounce in the exchanges of each pound weight converted into moneys, besides the gaine of coynage, which did rise to great revenue, making of thirtie pound weight Troyes, thirtie and two pound weight Towers; which is now out of use, and the Troy weight is onely used.

Gerard Malynes.
Vel Lex Mercatoria, or the Ancient Law-Merchant.…
London: Printed by Adam Islip, 1622.
Page 292.


Your committee think it necessary to observe, that besides the two Sorts of Pounds already mentioned, viz. the Standard Pound of twelve ounces, and the Merchant's Pound of fifteen ounces, there was a third Pound, called the Pound Tower, which was one sixteenth Part less than the legal Standard; This Pound Tower, Pound of the Tower, or Pound of the Weight of the Tower, as it is indifferently called in the Indentures of the Mint, is taken Notice of in the Statute 9 Henry 5, Chap. 2 and continued in Use till the 18th of Henry the 8th 1527, when it was abolished, as appears by a Parchment Roll in the Chapter House, Westminster, whereon, after a Verdict on a Trial of the Pix, there is the following entry:

Whereas hertofore the Marchaunte paid for Coynage of every Pounde Towre of fyne Gold, weying xi oz. qurt ii s. vi d. Now yt is determyned by the Kingis Highnes and his said Councelle (that the forsaid Pounde Towere shall be no more used and occupied) but Alman. of Goldes and Sylver shal be wayed by the Pound Troye, which maketh xii oz. Troye.

Report of the Carysfort Committee. (1758)


And whereas heretofore the merchant or other person bringing bullion unto the King's mint to be coined, paid for the coinage of every pound Tower weight, which was 11¼ ounces, 2 s. 6 d., in which Tower weight there was a difference from the Troy weight of three quarters of an ounce in a pound weight, it is now determined by the King's highness as afore that the said pound Tower shall be no more used or occupied, but that all manner gold and silver shall be weighed by the pound Troy being of 12 ounces Troy, which is three quarters of an ounce more than Tower weight as is aforesaid. For which cause the merchant or other person bringing gold to the mint to be coined shall pay for the coinage of every pound of weight Troy of fine gold, being 12 ounces, to be made into George nobles or half nobles, or any other the King's coins of fine gold, 2s. 9d.; and for the coinage of every pound weight of gold to be made into the crowns of the double rose or the half thereof, 3s. sterling.

A proclamation of Henry VIII, 5 November 1526.
Proclamation 112 in
Paul L. Hughes and James F. Larkin, editors.
Tudor Royal Proclamations. Volume 1.
New Haven: Yale University Press, 1964.


The two first kings after the Conquest coined only PENNIES, of which I have seen fourteen or fifteen different types. They agree, as near as can be judged, in weight and goodness, with the pennies of the Saxon kings, their immediate predecessors. It is therefore reasonable to think that king William introduced no new weight into his mints; but that the same weight used there for some ages after, and called the Pound of the Tower of London, was the old pound of the Saxon moneyers before the Conquest. This pound was lighter than the Troy pound* by three quarters of an ounce Troy, and did not very sensibly differ from twelve ounces of the weight still used in the money affairs of Germany, and there known by the name of the Colonia weight. And whereas the present standard of England, of eleven ounces two penny-weight fine, to eighteen penny-weight of allay, is called, in the oldest accounts of the mint extant, the Old Standard, or the standard of the Old Sterlings; it is most probable that these pennies were of that standard, and that the pound of the Tower of such standard silver, was then cut into 240 of these pennies. Whence the weight of the pennie will be found 22 Troy grains and a half, and the intrinsic value of twenty shillings, or of 240 such pennies of full weight, was the same as the value of 58 shillings and one pennie half pennie of our present coined money.

* The Troy weight, Pondus Trecense, from Troyes in Champagne, is generally supposed to have been introduced here by the Normans; but does not seem to have been immediately established. It is most probable that the Pound of the Tower, or the Moneyers pound, was also the pound in common use before the Conquest; and that it continued to be so for a considerable time after, till the Troy pound, perhaps from its greater weight) got the preference by degrees. It is observable, that in the old statute called Assisa panis et cerevisiae, 51 Hen. III and which it self refers to “older ordinances made in the time of the king's progenitors,” the weights of the several quantities of bread, etc. therein mentioned, are not expressed in Troy but in money weights, that is, in pounds, shillings, pennies, and farthings. “When a quarter of wheate is sold for xii d. then wastel breade of a ferthing shall weigh vi li. and xvi s. Bread cocket of a ferthing of the same corne and bultel, shall weigh more than wastel by ii s. Cocket breade made of corn that is of less price, shall weigh more than wastel by v s. A simnel of a ferthing shall weigh ii s. less than wastel, etc.” And by what follows in the same statute concerning weights, it should also seem that those weights, tho' commonly taken to have been the Troy weights, were not really so, but the money weights. “By consent of the whole realm of England the king's measure was made, that is to say, that an English pennie, which is called a sterling, round without clipping, shall weigh xxxii graines of wheate dry in the middest of the eare; and xx pence make an ounce, and xii ounces make a pound,” etc. For otherwise the penny weight here described, could never be, as the statute plainly implies, the true weight of the English coined pennie.

The weight of the Tower was also known in France, where it was called the Rochel or the English weight, concerning which I shall here transcribe a short quotation made by Du Fresne, in his Latin glossary upon the word MARCA, from what he calls a Regestum camerae computor. Paris “Ou royaume souloit avoir iv marcs: c'est assavoir le marc de Troyes, qui poise xiv sols, ii den. Esterlins de poix -le marc de la Rochelle, dit d'Angleterre, qui poise xiii s. iv den. Esterlins de poix.” In this passage I observe two particulars; first, that the Denier Esterlin is therein considered as the proper or natural part of the English or Rochel marc; and secondly, that the proportion of this marc to that of Troyes, which is here supposed to be that of 16 to 17; tho' not strictly the same as the proportion of the Tower to the Troy weight laid down in the table, yet differs as little from it as can well be expected from accounts taken with different standards, in different countries, at different times, and in ages when the standards of weights and measures, were neither made nor preserved with the same care they have since been. The proportion mentioned in the Table, being that of 15 to 16, is agreeable to a Verdict relating to the coinage of the 30 Oct. 18 Hen. VIII. remaining in the receipt of the Exchequer at Westminster, in which are the following words. “And whereas heretofore the marchaunte paid for coynage of every pounde Towre of fyne gold, weighing xi oz. quarter Troye, ii s. vi d. Nowe it is determyned by the king's highness, and his said councelle, that the forefaid Pounde Towre, shall be no more used and occupied, but al maner of golde and sylver shall be wayed by the pounde Troye, which maketh xii oz. Troye, which excedith the pounde Towre in weight iii quarters of the oz.” From hence it follows that the weight of the Tower pound was 5400 Troy grains, and that of the ounce or the twelfth part thereof 450 like grains. The weight of the Rochel or English ounce, as taken from the marc abovementioned, will be found 451.76 Troy grains, if the corresponding marc of Troyes is supposed exactly to coincide with the English Troy weight: and the present weight of the Colonia ounce, as stated by Joh. Gasp. Eisenschmid, from his own experiments, in his tract De ponderibus et mensuris, is 550 Paris grains and a quarter, which make, when reduced, 451.33 Troy grains.

Martin Folkes.
A Table of English Silver Coins, from the Norman Conquest to the Present Time….
London: Printed for the Society of Antiquaries, 1745.
Pages 3 - 5.


The following comparison of the Troy weight with Tower is in a MS. relating to Mint affairs in the Library of the Society of Antiquaries; the first page of which is signed by Sir Robert Cotton.

Troy Weight Tower Weight
A Grain.... is equal to.. a Grain and 8 Mites.
A Pennyweight dwt. 11 Grains and 2 Mites.
A Quarter of an Ounce Quarter and 8 Grains.
A Half Ounce Half and 16 Grains.
An Ounce Ounce and quarter and 2 Grains.
A Pound 12 Ounces 16 dwts.
A Journey of 30 lb. 32 lb.
100 lb 106 lb. and 8 Grains.

This Table appears to have been drawn up by some one connected with the Mint, from the minute divisions of the Grain, and from the technical term of a Journey, both of which are peculiar to that office.

Rogers Ruding.
Annals of the Coinage of Britain and its Dependencies. 2nd edition.
London: Lackington, Hughes, Harding, Mavor, and Jones, 1819.
Pages 18-19.


…And the Chronicon Pretiosum tells us, that from historians it appears, the Conqueror determined what the weight of the sterling penny, or penny weight, should be, to weigh 32 grains dry wheat. Consequently the standard penny weight was made equal to the weight of 32 grains wheat.

Succeeding kings confirmed William's charter; and even the great charter granted by king John, is only to explain and restore the ancient laws, which had been infringed. The statutes of 51st of Henry III. and 31st of Edward I. explain the ancient weights and measures; that is to say, the English penny called a sterling, round without clipping, was to weigh 32 grains dry wheat, taken from the midst of the ear, and 20 of those penny weights were to make an ounce, and 12 ounces a pound; and 8 of those pounds were to be a gallon of wine, and 8 of those gallons to make a London bushel, which is the ⅛ part of a quarter.

The definition of the penny weight in these statutes agrees with the determination of William the Conqueror, and shows the legal weight continued the same. What the weight of that pound was, so raised from a penny weight, equal to the weight of 32 grains of wheat, we may clearly learn from that declaration in the 18th of Henry VIII. when he abolished that old pound, and established the Troy weight; which says, that the Troy pound exceedeth the old Tower pound by ¾ of an ounce. As the Troy pound established by Henry VIII. is the same as is now in use, consisting of 5760 Troy grains, and 480 grain to the ounce, and 12 ounces to the pound: so 360 grains is ¾ of the ounce, which, deducted from 5760, leaves 5400 Troy grains, equal to that old Saxon pound which he abolished.

But to trace out experimentally the weight of that penny weight, raised from 32 grains of wheat, I got a small sample of dry wheat of last year 1773 (the wheat of that year but ordinary); and, from a little handful taken therefrom, I took out just 96 round plump grains, dividing them into parcels of 32 grains each, and all these weighted exactly 22½ Troy grains; consequently 240 such penny weights, which the old pound consisted of, were equal only to 5400 of our present Troy grains, conformable to the declaration of Henry VIII.

Henry Norris.
An Inquiry to Show, What Was the Ancient English Weight and Measure According to the Laws of Statutes, Prior to the Reign of Henry the Seventh.
Philosophical Transactions (1683 - 1775). Vol. 65 (1775), pages 48-58.

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