Caracalla Bronze Sestertius, RIC IV Caracalla 540A

Monetary Context and Severan Base-Metal Coinage

During the reign of Caracalla (sole ruler 211 to 217 AD), the Roman monetary system underwent notable structural changes. In 215 AD, the imperial treasury introduced the radiate double denarius, commonly designated modernly as the antoninianus, to address expanding military expenditures and state financial pressures. While silver coinage experienced adjustments in both fineness and tariffing, the traditional large base-metal denominations, specifically the sestertius and dupondius, maintained their established roles within domestic commerce and state payments. The sestertius, valued at four asses or one quarter of a silver denarius, continued to be struck on large flans of orichalcum or bronze alloy. Beyond its market utility, the sestertius retained immense ideological value due to the broad canvas provided by its physical dimensions. High-relief dies allowed the imperial administration to communicate complex political, military, and religious programs directly to the public in Rome and the western provinces. Struck under the traditional Senatorial formula indicated by the letters S C (Senatus Consulto), RIC IV Caracalla 540A represents this continuity of civic tradition during a transformative year in Severan monetary administration.

Production Standards and Minting at Rome

RIC IV Caracalla 540A was produced exclusively at the imperial mint in the city of Rome, which handled all primary production of bronze denominations for the central government. In 215 AD, Caracalla was engaged in military movements across the Danubian and eastern frontiers, yet the administrative machinery and core mint workshops at Rome operated continuously, issuing coins carrying meticulously updated imperial titulature. The production of Severan sestertii involved casting heavy, circular planchets from copper-alloy batches, followed by striking between hand-cut iron or bronze dies. Severan sestertii of this era typically adhere to an average weight standard clustering between 22 and 26 grams, with flan diameters generally ranging from 30 to 33 millimeters, though individual specimens naturally exhibit minor variations characteristic of ancient manual minting techniques. The die-engravers of the Rome mint demonstrated exceptional technical skill on this issue, achieving balanced compositions that accommodated extended imperial titles along the rims while maintaining high-relief figures on both faces.

Obverse Iconography and Imperial Portraiture

The obverse of RIC IV Caracalla 540A presents a dynamic, mature bust of Caracalla facing right. He is rendered laureate, draped, and cuirassed, combining three essential iconographic elements of imperial military and civic authority. The laurel wreath symbolizes victory and divine favor, while the cuirass (lorica) emphasizes his active role as commander-in-chief of the Roman legions. The delicate drapery (paludamentum) pinned at the shoulder underscores his official status as Augustus. Portraiture produced in 215 AD reflects the established mature style of Caracalla's sole rule, characterized by a furrowed brow, intensely focused gaze, short-cropped hair, and closely trimmed beard. This intense physiognomy departed from the classical Antonine serenity seen in late second-century issues, projecting formidable strength and resolve in accordance with Caracalla's self-fashioning as a soldier-emperor devoted to martial discipline.

Reverse Iconography: Diana in the Biga of Bulls

The reverse design of this sestertius features a distinctive and relatively uncommon numismatic image: the goddess Diana driving a biga of bulls (or oxen). Diana is depicted draped, standing left within the two-wheeled carriage, holding the reins as she guides the two beasts. Her mantle billows behind her in arched folds, conveying forward momentum and celestial motion. Above her brow rests a crescent moon, firmly identifying her role as Diana Lucifera, the bringer of light and embodiment of the nocturnal sky. The bull biga (biga boum) is an ancient mythological motif rarely chosen for imperial coinage, contrasting with the far more common biga or quadriga of horses. Historically associated with lunar deities, the horned bulls symbolize the crescent moon and terrestrial fertility. In the context of 215 AD, this celestial representation has been linked by scholars to religious observances surrounding Caracalla's visits to renowned eastern sanctuaries, such as the cult center of the Moon God (Men or Sin) at Carrhae, or local iterations of Artemis and Diana throughout Anatolia and northern Mesopotamia. The scene emphasizes celestial guidance and universal divine protection over the emperor and his campaigns.

Inscriptions and Epigraphic Analysis

The inscriptions on RIC IV Caracalla 540A provide precise chronological anchors and ideological statements. The obverse legend reads M AVREL ANTONINVS PIVS AVG GERM, expanding in Latin to Marcus Aurelius Antoninus Pius Augustus Germanicus. This formula highlights his official dynastic name linking him to the prestigious Antonine lineage, his piety (Pius), his supreme imperial authority (Augustus), and his celebrated military triumph over the Germanic tribes in 213 AD, which earned him the victory title Germanicus. The reverse inscription reads P M TR P XVIII IMP III COS IIII P P, followed by the letters S C placed in the fields or exergue. This legend expands as Pontifex Maximus, Tribunicia Potestate Duodevicesimum, Imperator Tertium, Consul Quartum, Pater Patriae, Senatus Consulto. The title Pontifex Maximus confirms his role as supreme religious pontiff, while TR P XVIII firmly dates the minting authority to the year 215 AD, when Caracalla held his eighteenth annual renewal of tribunician power. The imperial acclamation IMP III and his fourth consulship (COS IIII, attained in 213 AD) corroborate this administrative window. The closing formula S C denotes that the bronze coinage was issued under the formal decree of the Senate.

Typology and Chronological Classification

In the standard reference corpus Roman Imperial Coinage (Volume IV, Part I), this issue is catalogued as number 540A under the coinage of Caracalla's sole reign. It stands as a specific typological variant among the bronze issues of 215 AD, differentiated primarily by the reverse design of Diana driving the bull biga and the specific bust treatment on the obverse. While parallel reverse types were struck on precious-metal denominations such as gold aurei and silver denarii, the sestertius RIC IV Caracalla 540A offers the largest format for this particular compositional arrangement. The tight chronological window provided by TR P XVIII places the striking of this coin strictly between January 1 and December 31, 215 AD. Related contemporary issues from the Rome mint in this same year also celebrated Serapis, Apollo, and Asclepius, reflecting a focused imperial program of health, victory, and celestial piety during a phase when Caracalla suffered from recurrent physical ailments and sought divine intervention at major imperial sanctuaries.

Circulation Patterns and Archaeological Context

As a Rome-minted sestertius, RIC IV Caracalla 540A was released into widespread circulation across the central and western provinces of the Roman Empire, where base-metal aes denominations formed the backbone of day-to-day market transactions. Large bronze coins moved through military supply lines, urban markets, and tax administration networks in Italy, Gaul, the Rhineland, the Danube, and Hispania. Hoard evidence and site finds indicate that third-century sestertii frequently circulated for extended periods, occasionally remaining in commerce for decades until the severe monetary debasements and hyper-inflationary pressures of the mid-to-late third century led to their hoarding or gradual demonetization. Because the Diana in bull biga type represented a specialized thematic issue rather than a mass-market continuous type, it appears in lower frequencies in hoard records compared to standard military personifications like Virtus, Mars, or Victoria.

References

1. I Grandi Bronzi Imperiali, Vol. IV.1: Caracalla. p. 88
2. Description historique des monnaies frappées sous l'Empire romain, Tome IV. p. 174
3. Online Coins of the Roman Empire: RIC IV Caracalla 540A. ric.4.crl.540A
4. The Roman Imperial Coinage, Vol. IV, Part I: Pertinax to Geta. p. 302, no. 540A