Caligula Sestertius, RIC I (second edition) Gaius/Caligula 36

Monetary and Political Context

The accession of Gaius Caesar Augustus Germanicus, known historically as Caligula, in March of AD 37 occurred amid intense public anticipation following the reclusive final years of Tiberius. In early imperial Rome, the bronze and brass coinage executed at Rome played a dual role as high-volume transactional currency and an effective medium for public communication. The monetary framework established by Augustus organized the base-metal denominations into a bimestral brass and copper hierarchy: the sestertius and dupondius were struck in orichalcum, a golden-toned copper-zinc brass, while the as and quadrans were produced in pure copper. The sestertius functioned as the anchor of the token coinage, holding an official value of four copper asses, two brass dupondii, or one quarter of a silver denarius. Because of its generous module and substantial flan, typically ranging between thirty-three and thirty-six millimeters in diameter and weighing approximately twenty-five to twenty-nine grams, the denomination afforded imperial authorities an expansive field for monumental artistic programs. Upon his accession, Gaius utilized this denomination to emphasize dynastic continuity and divine sanction. The traditional imperial portrait was conspicuously omitted from the obverse, replaced instead by the seated figure of Pietas. This design choice underscored the young emperor's devotion to his family and the imperial cult, actively publicizing his role in concluding long-delayed religious duties, notably the completion and dedication of the monumental temple dedicated to Divus Augustus in Rome.

Production and Mint Organization

All attested specimens of RIC I (second edition) Gaius/Caligula 36 were struck at the central imperial mint in Rome. Production of large brass denominations required sophisticated metallurgical control, specifically the cementation process used to produce orichalcum by heating copper with zinc ores such as calamine in the presence of charcoal. The resulting alloy offered a distinct golden appearance that visually set the sestertius and dupondius apart from pure red copper issues. The production of flans for this series involved casting heavy discs in open or two-part moulds, which were subsequently dressed, trimmed, and adjusted to conform to the prevailing standard of roughly one-twelfth of a Roman pound (libra). The dies were engraved by master artisans capable of executing dense multi-figure compositions and miniature architectural elevations with crisp relief. Striking required considerable physical force, often necessitating multiple synchronized strikes under heavy hammers while the flans were heated, ensuring that the elaborate multi-figure reverse scene and fine obverse drapery filled the die recesses completely. The presence of the letters S C across the reverse field reflects the formal authority of the Senate over base-metal minting in the capital, preserving the constitutional fiction of senatorial oversight established under the Augustan settlement while serving the communicative agenda of the Princeps.

Obverse Iconography

The obverse design of RIC I (second edition) Gaius/Caligula 36 is distinguished by the total absence of the reigning emperor's portrait, which was standard on nearly all preceding and contemporary imperial sestertii. Instead, the coin depicts the personification of Pietas seated left on an ornate, high-backed throne. Pietas is shown fully draped and veiled, embodying traditional Roman religious decorum, maternal care, and filial respect. In her extended right hand she holds a patera, a shallow libation dish used in sacrificial rites, signaling active religious devotion. Her left arm rests comfortably upon a small draped statuette representing a human figure standing upright upon an elevated basis facing forward. The identity of this diminutive attendant figure has been interpreted by numismatists either as a generic representation of one of the Virtues, such as Concordia or Spes, or as a symbolic allusion to imperial progeny and familial protection. By substituting Pietas for the living ruler, Gaius linked his administrative persona directly to the moral virtues of filial duty, reminding the Roman populace of his piety toward his deceased parents, Germanicus and Agrippina Senior, as well as his deified ancestors.

Reverse Iconography and Architecture

The reverse of the sestertius presents one of the most celebrated and complex architectural compositions in early imperial numismatics. The focal point of the scene is the frontal elevation of a monumental hexastyle temple, conventionally identified as the Temple of Divus Augustus situated near the Roman Forum and the foot of the Palatine Hill. The structure features six slender columns supporting a pediment adorned with sculptural relief and surmounted at the apex by a triumphant quadriga flanked by acroterial Victories. Floral garlands drape gracefully across the columns, indicating a festive, consecrated state. In the immediate foreground before the temple steps, Gaius appears as the chief officiant of the state religion. He is depicted veiled and wearing the traditional toga (capite velato), holding a patera in his right hand to pour a libation over a garlanded altar placed to the right. The emperor is assisted by two ritual attendants (victimarii): one leads a sacrificial bull toward the altar from the left, while a second attendant stands beside the altar holding an additional patera or ritual vessel. This tableau captures the solemn sacrifice performed by Caligula at the long-awaited dedication of the Augusteum in late August of AD 37, visually recording an imperial ceremonial triumph.

Inscriptions and Epigraphy

The inscriptions on RIC I (second edition) Gaius/Caligula 36 provide essential chronological anchors, imperial titles, and religious declarations. The obverse peripheral legend reads C CAESAR AVG GERMANICVS P M TR POT, punctuated at the bottom in the exergue by the word PIETAS. Rendered in fully expanded Latin, the titulature designates Gaius Caesar Augustus Germanicus, Pontifex Maximus, Tribunicia Potestate. The absence of an iterative numeral following TR POT indicates that the dies were prepared during the emperor's first tribunician year, spanning from his accession in March of AD 37 into early AD 38. The exergual legend PIETAS functions as an explanatory label for the seated figure above, defining the overarching virtue animating the issue. On the reverse, the legend is divided into two distinct components: the dedication DIVO AVG, prominently inscribed in the upper field across the pediment and temple superstructure, and the traditional formula S C flanking the sacrificial group in the lower field. DIVO AVG explicitly dedicates the scene to the deified Augustus, memorializing the temple and its sacrifices, while S C stands for Senatus Consulto, certifying that the issue was authorized by decree of the Senate.

Typological Development and Chronology

Within the typology of Caligula's coinage, RIC 36 is the initial issue of an important commemorative sequence. The initial strike is firmly dated to AD 37 and AD 38 based on the un-numbered TR POT title on the obverse. When Caligula's tribunician power was renewed in subsequent years, the Rome mint modified the obverse die legends to record TR POT II, TR POT III, and TR POT IIII, catalogued under separate numbers in the revised Roman Imperial Coinage (RIC 44, RIC 51, and subsequent variants). In addition to the updating of the tribunician count, later issues occasionally incorporated the title PATER PATRIAE (P P), an honour that Gaius accepted toward the end of AD 37 or early AD 38 but which was not consistently incorporated into every base-metal die series immediately. RIC 36 is thus distinguished from its later counterparts specifically by the pristine first-issue legend lacking iterative numerals and paternal titles. A related non-portrait sestertius struck during the same initial emission celebrated Caligula's three sisters, Agrippina, Drusilla, and Julia (RIC 33), underscoring a cohesive initial propaganda program aimed at celebrating the broader imperial family and divine lineage rather than the solitary military image of the new Princeps.

Circulation, Wear, and Survival

Sestertii of RIC 36 entered wide circulation throughout central Italy and were rapidly exported to Roman legionary garrisons, administrative centers, and commercial hubs across Gaul, Hispania, and the Rhine frontier. As the standard high-denomination token coin, sestertii experienced vigorous hand-to-hand use in everyday commercial exchanges, market settlements, and tax payments. Because Caligula's reign lasted less than four years and ended in his assassination in January of AD 41, coins carrying his name and titles were produced over a relatively brief interval compared to those of his predecessor Tiberius or his successor Claudius. Following his death, while the Senate did not pass a formal, uniform damnatio memoriae that obliterated all public bronze coinage, many of Caligula's sestertii were subject to targeted local defacement, damnatio gouges, or deliberate countermarking under Claudius. Countermarks such as NCAPR (often read as Nero Caesar Augustus Probavit or Nummus Cusus A Populo Romano) were frequently applied to sestertii of this era to revalidate worn or politically sensitive bronze. Surviving specimens show a spectrum of wear from heavily smoothed circulation specimens to well-preserved hoard pieces, reflecting sustained monetary utility extending well into the Flavian period.

References

1. Coins of the Roman Empire in the British Museum, Volume I: Augustus to Vitellius. pp. 152-153, nos. 41-43
2. Roman Coins from the Earliest Times to the Fall of the Western Empire. pp. 110-115
3. Online Coins of the Roman Empire: RIC I (second edition) Gaius/Caligula 36. ric.1(2).gai.36
4. The Roman Imperial Coinage, Volume I: From 31 BC to AD 69 (revised edition). p. 110, no. 36