Caracalla Copper-Alloy As

Monetary Context and Denominational System

Under the Severan dynasty, the copper-alloy as maintained its traditional place as the base unit of the Roman Imperial monetary system. Valued at one-sixteenth of a silver denarius, one-fourth of an orichalcum sestertius, and half of a dupondius, the as was essential for facilitating low-value everyday market exchange across Rome, Italy, and the militarized western provinces. While the sestertius served as the flagship medium for large bronze propaganda displays, the as offered broad exposure in domestic circulation. During the late second and early third centuries AD, the Roman currency system experienced inflationary pressure and gradual debasement within precious metal issues, most notably visible in the declining silver fineness of the denarius and the eventual introduction of the double denarius (antoninianus) in 215 AD. In contrast, the baseline denominational relationship of the base-metal coinage remained formally intact, preserving the core structure originally standardized under the Augustan currency reform centuries earlier.

Production Standards and Mint Organization

The overwhelming majority of imperial copper-alloy asses for Caracalla were produced at the capital mint of Rome. A small number of eastern or traveling military mint issues have been proposed or debated in scholarly literature for Severan base metal, but centralized metropolitan striking remained the definitive norm for regular Roman imperial aes coinage. The as was conventionally struck on unalloyed copper or low-zinc copper-alloy flans, distinguishing it metallurgically from the golden-hued orichalcum (brass) employed for the sestertius and dupondius. Production standards for the as under Caracalla targeted a nominal weight standard between approximately 9.0 and 11.5 grams, with module diameters generally spanning 24 to 27 mm. Metrological analyses indicate considerable dispersion in finished striking weights, reflecting the ancient mint practice of striking base-metal flans al marco (a fixed number of blanks cut from a specified pound of metal) rather than calibrating each individual blank al pezzo.

Obverse Iconography and Imperial Portraiture

Obverse portraiture on the asses of Caracalla provides a chronological visual record of his physical and political development. During his tenure as Caesar (196 to 198 AD), portraits render Caracalla as a young boy, typically depicted bare-headed, draped, and occasionally cuirassed. Following his elevation to Augustus in 198 AD, the iconography shifts to introduce the laureate wreath, marking full imperial standing. In the mid-Severan period, the portraiture traces his adolescence and early adulthood, featuring soft features that gradually give way to short side-whiskers and a cropped beard. By his sole reign (211 to 217 AD), the portrait evolves into its most recognizable stylistic form: a compact, muscular bust crowned with a laurel wreath, characterized by a furrowed brow, deeply set eyes, tightly curled hair and beard, and a severe, hostile expression reflecting his self-stylization as a stern soldier-emperor and admirer of Alexander the Great.

Reverse Iconography and State Typology

The reverse repertoire on Caracalla's asses reflects the shifting public priorities and ideological programs of his rule. Early Caesar issues heavily emphasize priestly implements (lituus, simpulum, tripod, patera) to advertise his co-optation into the priestly colleges and his status as designated successor. During the joint reign with Septimius Severus and later Geta, reverse types promoted dynastic harmony (Concordia, Aeternitas) and joint military prestige, notably featuring Victory erecting trophies, captives seated at the base of trophies, and scenes celebrating the British campaigns between 208 and 211 AD. During Caracalla's sole rule, the reverse imagery became increasingly martial and religious. Significant types include Mars advancing with spear and trophy, Serapis holding a scepter and raising his right hand, Sol in his radiant majesty, Aesculapius accompanied by Telesphoros, and elaborate representations of the Emperor sacrificing over an altar, addressing the legions (adlocutio), or riding in a triumphal quadriga.

Inscriptions and Epigraphic Formulas

Legends on Caracalla's asses document the constitutional titles and imperial accolades acquired throughout his life. Early obverses bear the formula M AVR ANTONINVS CAES or M AVR ANTON CAES PONTIF. Upon his elevation to Augustus, the titular legend expands to M AVREL ANTONINVS PIVS AVG, subsequently incorporating cognomina ex virtute such as BRIT (Britannicus) and GERM (Germanicus). Reverses regularly register the emperor's tribunician power (TRIB POT, later abbreviated as TR P with iter numbers up to TR P XX in 217 AD), consulships (COS through COS IIII), and imperial acclamations (IMP). Virtually all regular imperial copper-alloy asses bear the letters S C (Senatus Consulto) on the reverse field or exergue, preserving the constitutional fiction of senatorial authority over base-metal token coinage even amidst military despotism.

Typological Evolution and Chronological Phases

The typological evolution of Caracalla's asses divides into three overarching chronological phases. The first phase spans his youth as Caesar from 196 to early 198 AD, focusing on dynastic legitimacy and traditional piety. The second phase, covering the joint reign as Augustus from 198 to late 211 AD, incorporates extensive issues commemorating the Parthian campaigns, the decennalia, the British campaigns with Septimius Severus, and strained invocations of brotherhood alongside Geta. The final phase, encompassing his sole reign from late 211 to April 217 AD, displays annual updates of tribunician numerals (TR P XV to TR P XX) paired with consulships. This terminal phase highlights Caracalla's monumental public works, his reverence for healing deities such as Aesculapius and Apollo following bouts of severe illness, and intense military operations along the northern frontier and against Parthia.

Circulation Patterns and Archaeological Context

Archaeological evidence from hoards and site finds confirms that Caracalla's asses circulated extensively throughout Roman Italy, the Rhine-Danube limes, and the western provinces of Gaul and Britain. Because base-metal coinage suffered negligible international trade leakage compared to silver and gold, these asses remained active in local markets for decades after Caracalla's death, often circulating alongside worn bronze issues of the Antonine dynasty. By the mid-third century AD, general economic disruption and the dramatic proliferation of debased radiate antoniniani led to a gradual decline in the production and circulation of fractional copper-alloy denominations, rendering the Severan period the final flourishing era for regular imperial as issues of classic high-relief style.

References

1. I Grandi Bronzi Imperiali: Caracalla. volume VI-1
2. Coins of the Roman Empire in the British Museum, Vol. V: Pertinax to Elagabalus. pages 174-490
3. Description historique des monnaies frappees sous l'Empire Romain, Tome IV. pages 140-220
4. The Roman Imperial Coinage, Vol. IV, Part I: Pertinax to Geta. pages 211-313