The principal Roman coins were the as, of copper; the sestertius, quinarius, denarius, of silver; and the aureus, of gold.

1. The as, the unit of the Roman currency, contained originally a pound of copper, but it was diminished from time to time till at last it contained only 1/24 of a pound.

Note.--An as, whatever its weight, was 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 is also used as a general unit of measure. Thus--

a) In Weight, the as is a pound, and the uncia an ounce.

b) In Measure, the as is a foot or a jugerum, and the uncia is l/12 of a foot or of a jugerum.

c) In Interest, the as is the unit of interest -- i.e., 1 percent a month or 12 percent a year; the uncia is l/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.

Computation of Money

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).

Weights and Measures

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 of Roman weights.

a) The libra, like the as in money, is divided into 12 parts.

2. The Modius, equal to about a peck, is the basis of dry measure.

3. The Amphora, containing a Roman cubic foot, equivalent to about seven gallons, is a convenient basis of liquid measure.

4. The Roman Pes or Foot, equivalent to about 11.6 inches, is the basis of long measure.

Note.-- Cubitus is equivalent to 1 1/2 Roman feet, passus to 5, and stadium to 625.

5. The Jugerum, containing 28,800 Roman square feet, equivalent to about six tenths of an acre, is the basis of square measure.