The Roman As

Roman Bronze Coins

Republican Period

The as, or more precisely the aes grave (or aes librale), was the earliest official Roman coin. The coin was made of bronze and was initially cast, later transitioning to hammered striking. The intrinsic bronze value was tied to ancient Roman weight units, with an initial standard equal to a Latin pound (273 g), subsequently adjusted to the full Roman pound (327 g).

Several series of this heavy cast bronze currency were produced, the earliest being the "Janus and Mercury" series, named after the divine effigies depicted on the coin, along with the mark "I" signifying the value of "one as".

During the Republic, around 225 BC and contemporary with the introduction of the quadrigatus, the celebrated "prow series" was introduced, named after the galley prow featured on the reverse.

The final major cast series was the "wheel series", characterized by a six-spoke chariot wheel on the reverse.

Submultiples of the As

The as had fractional denominations organized on a duodecimal system based on the uncia (ounce), another core Roman weight unit. The fractional denominations are listed below with their obverse imagery and value marks:

The semis (plural semisses) was the bronze coin worth half an as, or six unciae. Its value was marked by an 'S' on the reverse alongside a ship's prow, while the obverse bore the portrait of Saturn. Initially cast, it began to be struck shortly before the Second Punic War (218–201 BC). It was minted sparingly during the Empire, ending under Hadrian (117–138 AD). In Byzantine coinage, the semis designated half a gold solidus.

The triens (plural trientes) was worth one third of an as, or four unciae. The standard type featured Minerva with four pellets on the obverse and a galley prow on the reverse. Striking ceased around 89 BC.

The quadrans (literally "a fourth") was worth 1/4 as (three unciae), indicated by three pellets. It bore the head of Hercules on the obverse and a galley prow on the reverse. Following the semuncial reform of 90 BC, the quadrans was the lowest circulating denomination struck, enduring until Antoninus Pius (138–161 AD).

The sextans was worth one sixth of an as (two unciae), marked with two pellets and featuring Mercury on the obverse and a prow on the reverse.

The uncia (ounce) was worth 1/12 as, marked with a single pellet. The obverse showed helmeted Roma. During the Empire, it was briefly revived under Trajan and Hadrian with the reverse legend SC.

Other rare bronze fractions connected to the as system included:

• The bes: worth two thirds of an as (8 unciae), struck only in 126 BC by C. Cassius;
• The dodrans: worth 3/4 as (9 unciae), an exceptionally rare issue minted concurrently with the bes;
• The quincunx: worth 5/12 as (5 unciae), used primarily in Central and Southern Italy during the Second Punic War;
• The semiuncia (half ounce): 1/24 as, depicting Mercury or an acorn, struck until the introduction of the denarius in 211 BC.

Multiples of the As

The principal heavy bronze multiples included:

The dupondius was worth 2 asses (1/2 sestertius). Under Augustus' 23 BC reform, it was minted in golden brass (orichalcum), while lower denominations used pure red copper. Under Nero (66 AD), the dupondius was distinguished from the as by adding a radiate crown to the emperor's head.

The tripondius was a rare multiple worth three asses, bearing the mark 'III'.

The decussis was a massive bronze multiple worth 10 asses, marked 'X'. A celebrated specimen weighing 1,107 g is preserved at the National Roman Museum. It was quickly superseded in value by the silver denarius.

Devaluation of the As during the Republic

The weight of the as was progressively reduced across republican history:

• Librale standard: full Roman pound of 327 g at its inception;
• Semilibral standard: 1/2 pound (163 g) around 286–217 BC;
• Sextantal standard: 1/6 pound (54.5 g) introduced around 214–211 BC;
• Uncial standard: 1 uncia (27.25 g) established by the Lex Flaminia in 217 BC;
• Semuncial standard: 1/2 uncia (13.6 g) enacted by the Lex Plautia Papiria in 89 BC.

Imperial Period

Under Augustus' monetary reform of 23 BC, the as was standardized at 1/30 Roman pound (10.91 g) and struck in pure red copper (aes), distinct from orichalcum. Under senatorial authority, it bore the prominent reverse mark SC (Senatus Consulto).

The as remained the fundamental daily base denomination of the High Empire until the mid-3rd century AD. In the Greek-speaking eastern provinces, bronze denominations were known as the assarion (plural assaria).

Where 'Æ' stands for aes (bronze/copper). In modern numismatics, the classification Æxx denotes the exact diameter in millimetres.