Caligula As: RIC I (second edition) Gaius/Caligula 58

Monetary Context and Historical Background

When Caligula acceded to the imperial purple in March of AD 37 following the death of Tiberius, he inherited an empire characterized by administrative stability yet marked by simmering political anxieties within the senatorial order and the wider populace. Caligula possessed an impeccable pedigree connecting him to both the Julian and Claudian lineages, being the son of Germanicus and Agrippina the Elder. His maternal grandfather was Marcus Vipsanius Agrippa, Augustus's most capable general and trusted collaborator. Unlike Tiberius, whose late reign saw a marked contraction or conservatism in base-metal output, Caligula inaugurated a dynamic monetary policy designed to celebrate his illustrious forebears. By issuing a substantial series of copper asses honoring Agrippa, the young princeps highlighted the heroic military origins of his maternal family. The as held a central place in the Roman denominational structure as the everyday base-metal coin of domestic transactions, tariffed at four asses to the sestertius and sixteen to the silver denarius. Commemorative imagery placed on the as reached the hands of everyday Roman citizens, soldiers, and merchants across the provinces, functioning as widespread imperial communication that coupled dynastic prestige with traditional religious and military virtues.

Mint Production and Technical Standards

The production of RIC I (second edition) Gaius/Caligula 58 occurred at the principal imperial mint in Rome. Under the early Roman Empire, the as was typically struck in unalloyed red copper, distinguishing it in color, metal, and value from the yellow brass or orichalcum allocated to the sestertius and dupondius. The nominal target weight for an Augustan and Julio-Claudian copper as hovered around 10.9 grams, though individual surviving specimens demonstrate the typical variations of ancient hammered production, commonly ranging between 9.5 and 11.5 grams. Flans were cast in circular molds before being struck between engraved iron dies, frequently resulting in subtle bevels along the flan edges. Die axes for this issue predominantly conform to a regular six-o'clock or twelve-o'clock orientation, reflecting the mechanical discipline of the urban mint. The immense scale of production required numerous die pairs, and die studies reveal minor stylistic shifts in the rendering of Agrippa's profile and Neptune's proportions, attesting to multiple active workshops within the mint. Contemporary imitation was also widespread in the western provinces, where military and commercial demand for fractional currency led local workshops in Gaul and Britain to produce cast or locally struck copies with lighter weights and crude letterforms.

Obverse Iconography

The obverse of RIC 58 presents a heroic portrait of Marcus Vipsanius Agrippa facing left. Unlike typical imperial coinage where the reigning emperor appears, this issue features a deceased statesman whose death occurred decades earlier in 12 BC. Agrippa's portrait is rendered in a severe, veristic style that echoes late Republican portraiture while embracing the classicizing polish of the Augustan epoch. His features include an aquiline nose, prominent brow, firmly set mouth, and strong jawline, conveying gravitas and military authority. The defining iconographic attribute of the portrait is the rostral crown (corona rostralis), composed of gold bands adorned with stylized ship beaks or rams (rostra). In Roman tradition, the corona rostralis was one of the highest military decorations, awarded only to commanders who had achieved extraordinary naval victories. Agrippa was uniquely honored with this crown following his triumph over Sextus Pompey at the Battle of Naulochus in 36 BC, and he maintained this maritime attribute across Augustan state art and subsequent commemorative numismatics.

Reverse Typology

The reverse design features Neptune, the Roman god of the sea, standing facing left in a powerful contrapposto posture. A light cloak or mantle (chlamys) is draped loosely over his shoulders or left arm, leaving his muscular torso exposed in classical heroic nude convention. In his extended right hand, Neptune holds a dolphin pointing downward, a familiar symbol of marine tranquility, speed, and divine favor upon the waves. In his left hand, the deity grasps a vertical trident, the emblem of naval dominion and divine power. Flanking Neptune in the left and right fields are the large letters S and C. The figure of Neptune directly complements the obverse portrait of Agrippa, emphasizing the commander's naval mastery and crediting divine patronage for the maritime triumphs that brought peace to the Roman world. The design possesses an elegant balance, with the vertical line of the trident grounding the composition against the dynamic curves of the dolphin and mantle.

Inscriptions and Epigraphy

The inscriptions on RIC 58 are concise, elegant, and strictly traditional in their epigraphic formulation. The obverse legend reads M AGRIPPA L F COS III, beginning from the lower left and running clockwise around the portrait. The epigraphy unpacks according to standard Roman naming and magistracy conventions: 'M[arcus] AGRIPPA L[ucii] F[ilius] CO[n]S[ul] III', translating as 'Marcus Agrippa, son of Lucius, consul for the third time.' Agrippa entered his third consulship in 27 BC alongside Augustus, a landmark year that marked the constitutional inauguration of the Augustan principate. The reverse bears no titular inscription around the rim, carrying solely the monumental letters S C across the horizontal field. These characters stand for 'Senatus Consulto' ('By decree of the Senate'), signaling that the bronze and copper denominations were authorized through senatorial decree in accordance with established Augustan monetary arrangements. The lettering is cut in clean, serifed imperial capitals with even spacing, representing the mature lapidary style developed in Augustan and early Julio-Claudian Rome.

Typology and Chronological Classification

The chronological placement of the Agrippa Neptune as has generated extensive numismatic debate. Because the obverse legend cites Agrippa's historical consulship of 27 BC and the reverse lacks imperial titles or tribunician dating for the ruling princeps, the type itself is undated on its face. Early twentieth-century cataloguers, including Harold Mattingly in the first edition of Roman Imperial Coinage, suggested that the type originated under Tiberius, perhaps around AD 23 to 31 following the death of Drusus the Younger. However, in the 1984 revised second edition of RIC I, C. H. V. Sutherland classified the main production of RIC 58 under the reign of Caligula between AD 37 and 41. Detailed hoard evidence, stratigraphic data from military sites in Germany and Britain, and countermark studies (notably the TIB AVG and later Claudian stamps) demonstrate that the overwhelming majority of these coins entered circulation concurrently with the secure issues of Caligula. While some scholars hold open the possibility of inaugural striking late in Tiberius's reign or subsequent re-striking under Claudius, the consensus reflected in modern reference catalogues places RIC 58 as a cornerstone of Caligula's ideological program.

Circulation and Archaeological Distribution

RIC 58 enjoyed an extraordinarily broad and enduring circulation across the Roman Mediterranean and the northern military frontier. Archaeological excavations regularly turn up Agrippa asses in Italy, Gaul, the Rhineland, the Iberian peninsula, and Roman Britain. Because Caligula ruled for less than four years, the massive volume of these coins meant they continued to circulate long after his assassination in AD 41. Unlike coins explicitly bearing Caligula's name and image, which were occasionally defaced or withdrawn following his unofficial damnatio memoriae, the Agrippa asses were immune to dynastic opprobrium because they commemorated an uncontested hero of the early Empire. Many specimens found in frontier forts exhibit substantial wear, indicating decades of daily handling through the reigns of Claudius, Nero, and the Flavian dynasty. Furthermore, official and semi-official countermarks applied during the Claudian invasion of Britain and along the Rhine legionary bases confirm their prolonged utility in meeting the monetary needs of frontier garrisons.

References

1. Coins of the Roman Empire in the British Museum, Volume I: Augustus to Vitellius. pp. 142-143, nos. 102-108
2. Online Coins of the Roman Empire: RIC I (second edition) Gaius/Caligula 58. RIC I (second edition) Gaius/Caligula 58
3. Roman Provincial Coinage, Volume I: From the Death of Caesar to the Death of Vitellius. pp. 8-10
4. The Roman Imperial Coinage, Volume I: From 31 BC to AD 69 (Revised Edition). pp. 112-113, no. 58