Caligula Sestertius, RIC I (second edition) Gaius/Caligula 44

Monetary and Denominational Context

The monetary system of the early Roman Empire, established under Augustus and maintained by his Julio-Claudian successors, was structured around a bimetallic and base-metal hierarchy centered on the silver denarius and the gold aureus. Within this framework, the sestertius served as the largest regular base-metal denomination and the fundamental unit of account in Roman commerce, imperial administration, and fiscal accounting. Valued at four asses, two dupondii, or one quarter of a denarius, the sestertius held substantial purchasing power within the domestic economy of Italy and the western provinces. Struck in orichalcum, a golden-toned brass alloy composed of copper and zinc, the sestertius was visually and physically distinct from the pure copper asses and quadrantes. Under Caligula, the production of aes coinage was marked by significant programmatic ambition. While earlier Julio-Claudian rulers frequently used base-metal coinage to honor deceased family members or promote administrative virtues, Caligula utilized the broad flan of the sestertius to present intricate pictorial compositions that engaged directly with monumental architecture, religious festivals, and dynastic honors. Type RIC I (second edition) Gaius/Caligula 44 represents an important manifestation of this policy, balancing civic religiosity with imperial public relations on Rome's most visible fiat currency.

Production Standards and Mint Attribution

The issue RIC I (second edition) Gaius/Caligula 44 was struck exclusively at the principal imperial mint in Rome. While some earlier scholarship considered the possibility of provincial branch mints operating in Gaul (such as Lugdunum) for specific early imperial aes coinages, modern stylistic and metallurgical analyses have firmly placed the vast majority of Caligula's official sestertii at the capital. Production of sestertii at Rome followed rigorous technical procedures. Flans were cast in circular open or two-part molds before being heated and struck between hardened intaglio bronze or iron dies. The target weight standard for orichalcum sestertii during this period averaged approximately 27.5 to 28.5 grams, although surviving specimens naturally exhibit a wider operational distribution due to ancient production tolerances, typically ranging from 25 to over 30 grams, with flan diameters spanning between 34 and 37 millimeters. Die alignment on these Rome issues is predominantly regular, adhering closely to a vertical six o'clock or twelve o'clock axis. The high relief of the temple scene and the deep seated posture of Pietas required immense striking force, often necessitating multiple hammer blows on a hot flan to bring up full detail in the central fields.

Obverse Iconography and Variations

The obverse design departs strikingly from the conventional imperial portraiture that dominated western Roman bronze coinage. Instead of the laureate or bare head of Caligula, the die features a full-length personification of Pietas. She is shown veiled and draped, seated facing left on an ornate, high-backed throne. In her extended right hand, she holds a patera, a shallow libation dish essential to Roman sacrificial ritual. Her left arm rests gracefully upon the head of a small, draped figure that stands facing on an elevated plinth or basis. This diminutive attendant figure has generated diverse scholarly interpretations; some numismatists view it as an personification of youth, while others interpret it as a domestic or cultic statuette symbolizing ancestral tutelage or the broader protection of the domus Augusta. The placement of the title PIETAS across the exergue or woven into the legend anchors the moral and religious theme of the coin, emphasizing Caligula's dutiful adherence to familial and state religious obligations.

Reverse Iconography and Temple Architecture

The reverse of RIC I (second edition) Gaius/Caligula 44 presents an elaborate architectural and ritual scene that ranks among the most celebrated compositions in Julio-Claudian numismatics. The focal point of the composition is the facade of a hexastyle (six-columned) temple draped with festive garlands. The pediment and roofline are surmounted by sculptural groups, notably a prominent central quadriga flanked by acroterial statues. This edifice is widely identified as the newly completed Temple of the Deified Augustus (Templum Divi Augusti) in Rome, begun under Tiberius and dedicated by Caligula in late August of AD 37. In front of the temple facade, a sacrificial ceremony is depicted in meticulous detail. Caligula himself appears veiled and togate (capite velato), standing right before an ignited, garlanded altar, pouring a liquid offering from a patera. He is assisted by two sacrificial attendants (victimarii): one leads a garlanded bull toward the altar, while the second stands ready holding an additional ceremonial vessel. The letters S C (Senatus Consulto) flank the scene, affirming the formal senatorial authority under which base-metal coinage was authorized.

Inscriptions and Epigraphy

The epigraphy of RIC I (second edition) Gaius/Caligula 44 is executed in the crisp, monumental Roman capital script typical of the urban mint under the early principate. The obverse legend reads: C CAESAR AVG GERMANICVS P M TR POT, accompanied by the exergual inscription PIETAS. The titular elements abbreviate Gaius Caesar Augustus Germanicus, Pontifex Maximus (chief priest), and Tribunicia Potestate (holder of the tribunician power). The inclusion of PIETAS clarifies the programmatic theme of the design, linking the personification directly to the princeps's public persona. The reverse legend is succinct yet potent: DIVO AVG S C. The dedication DIVO AVG (Divo Augusto, 'To the Deified Augustus') identifies the dedication of the temple depicted in the background, making clear that the sacrifice performed by Caligula is offered directly in honor of his divinized great-grandfather. The mark S C signifies Senatus Consulto ('by decree of the Senate'), marking the traditional legal sanction of civic bronze coinage in Rome.

Typological Development and Chronology

Caligula's Pietas sestertii were struck across several phases of his reign, forming a coherent sequence categorized by variations in the imperial tribunician numbering and the layout of the obverse legend. The prototype of this series commenced in the first year of his principate (AD 37 to 38, catalogued as RIC 36), carrying the initial, unnumbered designation TR POT. Subsequent annual renewals of the tribunician power were reflected on updated dies: TR POT II for AD 38 to 39, TR POT III for AD 39 to 40, and TR POT IIII for AD 40 to 41. RIC I (second edition) Gaius/Caligula 44 specifically captures an issue phase datable to AD 39-40, reflecting the continued celebration of the Augustan cult and the dedication of the temple even after the initial festivities of AD 37. Within this catalogue type, minor die variations exist in the precise rendering of the temple pediment sculptures, the positioning of the sacrificial bull, and the spacing of the exergual lettering, reflecting the work of multiple die engravers operating within the Rome officinae during this production cycle.

Circulation Patterns and Monetary Afterlife

Sestertii of Caligula entered heavy circulation across the Roman heartland of central and northern Italy, as well as along key military corridors and commercial networks in Gaul, the Rhine frontier, and the Iberian Peninsula. Because of their substantial intrinsic and denominational value, these large orichalcum coins remained in active use for decades after Caligula's death. Following his assassination in January of AD 41, the Roman Senate debated a formal damnatio memoriae against the fallen emperor, leading to the deliberate defacement, countermarking, or melting of many of his aes coins. However, because RIC 44 prominently depicted Pietas rather than Caligula's own facial portrait on the obverse, and celebrated Divus Augustus on the reverse, specimens of this specific design often avoided aggressive mutilation or early withdrawal. As a result, many examples survived in prolonged circulation, frequently exhibiting heavy smoothing, edge bruising, or countermarks applied under Claudius or Nero before eventually being lost or deposited in hoards of the Flavian and Trajanic periods.

References

1. The Coinage of Caligula: Imperial Ideology and Monumental Representation. pp. 41-58
2. Coins of the Roman Empire in the British Museum, Volume I: Augustus to Vitellius. pp. 152-156
3. Online Coins of the Roman Empire: RIC I (second edition) Gaius/Caligula 44. ric.1(2).gai.44
4. The Roman Imperial Coinage, Volume I: From 31 BC to AD 69 (Revised Edition). pp. 110-112, no. 44