N V M M I   R O M A N I  (E T   A L I A)

Titus Bronze Sestertius, 80 AD

Euro, 5 cents, 2003
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This is a serious page on Roman coins, weights and measures. If you are looking for the Colosseum on coins click here.

The principal Roman coins
were the as, made of copper; the sestertius, the quinarius, the silver denarius and the golden aureus.
1. The as, the unit of the Roman currency, was originally one pound of copper, but its value diminished with time till at last it contained only 1/24 of a pound.
Note:  An as, whatever its weight, was always divided into twelve unciae.
2. The sestertius contained originally 2 1/2 asses, the quinarius 5, and the denarius 10; but as the as depreciated in value, the number of asses in these coins was increased.
3. The as was also used as a general unit of measure. Thus:

a) In Weight, the as is one libra, or pondo, which means "weight" (~ 327 g), and the uncia - one ounce - is 1/12 of the as (~ 27 g).
b) In Measure, the as is a foot - 29.6 cm (11.6 inches) - and the uncia is 1/12 of a foot (24.6 mm).
c) In Interest, the as is the unit of interest -- i.e., 1 percent a month or 12 percent a year; the uncia is 1/12 percent a month, or 1 percent a year; and the semis is 6/12 percent a month, or 6 percent a year, etc.
d) In Inheritance, the as is the whole estate, and the uncia 1/12 of it. Hence heres ex asse, heir of the whole estate; heres ex dodrante, heir of 9/12.

Now, why dodrante? It is the ablative case of dodrans, dodrantis (masculine), that is a mix of de and quadrans, and that means "missing 1/4 of the unit". The unit is the as so here it means "owner of 3/4", that is the same of 9/12.
Dodrans could also be a measure of length (3/4 of a foot): "quinque pedes et dodrans" and of time: "dodrantes horarum", i.e. 3/4 of an hour (which in any case had a very different length then).  
A nice page on Roman units of measure is of course in Wikipedia.

Computation of Money and Complications on sesterces
1. In all sums of money the common unit of computation was the sestertius, also called nummus; but four special points deserve notice:
a) In all sums of money, the units, tens, and hundreds are denoted by sestertii with the proper cardinals. Thus --
         quinque sestertii = 5 sesterces;
         viginti sestertii = 20 sesterces;
         ducenti sestertii = 200 sestertes.
b) One thousand sesterces are denoted by mille sestertii, or mille sestertium.
c) In sums less than 1,000,000 sesterces, the thousands are denoted either (1) by milia sestertium (gen. plur.), or (2) by sestertia:
duo milia sestertium, or duo sestertia = 2,000 sesterces;
quinque milia sestertium, or quinque sestertia = 5,000 sesterces.
Note.--With sestertia the distributives are generally used, as -- bina sestertia.
d) In sums containing one or more millions of sesterces, sestertium with the value of 100,000 sesterces is used with the proper numeral adverb, decies, vicies, etc. Thus--
decies sestertium = 1,000,000 (10 x 100,000) sesterces;
vicies sestertium, 2,000,000 (20 x 100,000) sesterces.

In the examples under d), sestertium is treated as a neuter noun in the singular, though originally it was probably the genitive plural of sestertius, and the full expression for 1,000,000 sesterces was decies centena milia sestertium. The words centena milia were afterward generally omitted, and finally sestertium lost its force as a genitive plural, and became a neuter noun in the singular, capable of declension.

2. Sometimes sestertium is omitted, leaving only the numeral adverb: as, decies = 1,000,000 sesterces.

3. The sign HS is often used for sestertii, and sometimes for sestertia, or sestertium:
- decem HS = 10 sestercies (HS = sestertii)
- dena HS = l0,000 sesterces (HS = sestertia)
- decies HS = 1,000,000 sesterces (HS = sestertium)

The following weights and measures deserve mention:
1. The Libra, also called As or Pondo, equal to about 11 1/2 ounces, is the basis for Roman weights.
    a) The libra, like the as in money, is divided into 12 parts.
2. The Modius, equal to ~ 8 2/3 of a liter (about a peck) is the basis for dry measure.
3. The Amphora, containing a Roman cubic foot, equivalent to about seven gallons, is a convenient basis for liquid measure.
4. The Roman Pes or Foot, equivalent to about 29.6 cm (11.6 inches) is the basis for length measure.   

Note.-- The Cubitus is equivalent to 1 1/2 Roman feet (44.4 cm), the passus to 5 feet (1.48 m), and the stadium to 185 m (625 feet). Consequently mille passuum - the Roman mile, was 1480 metres.5. The Jugerum, containing 28,800 Roman square feet, equivalent to about six tenths of an acre, is the basis for square measure.

Weights and measures
Good websites on Weight and measures here and here.


The following text is taken, with a few changes, from a disappeared website of Abram Ring (now on YouTube).

The sestertius (Eng. sesterce> sehs-tursh) was the main coin used for setting prices and values.  The word is formed from semis-tertius = 2 1/2.   Also, as aureus, denarius, and other coin names, the name was originally an adjective modifying nummus, the Roman word for "coin".   Before the Second Punic War the sestertius was worth 2 1/2 asses because this was a convenient value, since 10 asses = 1 denarius.   Early in the war due to hard times the as was devalued to 4 asses = 1 sestertius, which made 16 asses = 1 denarius.
     Due to the greatly different nature of today's economics, any effort to equate sesterces to modern currency is probably wasted.  However, we can look at what was the money situation of  different Romans. Consider the facts below:









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As - 37 BC








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Republican Sestertius








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Quinarius - about 230 AD








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Denarius - 130 BC








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Aureus - about 240 AD








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Victory !!