Agrippina Sestertius, RIC I (second edition) Gaius/Caligula 55

Monetary and Political Context

The sestertius occupied a central position within the Augustan monetary system as the premier large-format bronze denomination, struck in orichalcum (a bright golden copper-zinc alloy) with a value equal to four asses or one quarter of a silver denarius. Because of its expansive surface area and broad domestic circulation in Italy and the western provinces, the sestertius served as an ideal medium for high-impact imperial communication. When Caligula succeeded Tiberius in March AD 37, the political climate in Rome was shaped by relief at the end of Tiberius's reclusive and suspicious final years, alongside an intense expectation that the tragic fate of Germanicus's household would be redressed. Germanicus and Agrippina the Elder had been celebrated by the Roman plebs and senate alike, but their surviving family had suffered severe purges under Tiberius and the praetorian prefect Sejanus. By dedicating prominent aes denominations to his deceased mother and brothers, Caligula satisfied popular grief and projected filial piety (pietas). The issue of RIC I (second edition) Gaius/Caligula 55 transformed the private tragedy of the imperial family into a public reaffirmation of Julio-Claudian legitimacy, asserting that the new regime derived its sanction from the bloodline of Augustus through Agrippina.

Mint Location and Production Standards

All regular imperial issues of RIC I (second edition) Gaius/Caligula 55 were produced at the central mint of Rome. The workshop operated under senatorial administrative convention for base-metal coinage, as indicated by the prominent formulaic inscription S C (Senatus Consulto) implied by the senatorial dedication on the reverse. Like other Julio-Claudian sestertii, the coin was struck on substantial cast flans composed of orichalcum. The standard weight for sestertii during this reign typically centered around 27.0 to 29.0 grams, with individual specimens fluctuating based on blank preparation tolerances and flan casting consistency. Diameters typically range between 35 and 37 millimeters, affording die engravers ample space for intricate architectural, vehicular, and portrait modeling. The die axis was predominantly struck at 6 o'clock or 12 o'clock, reflecting the regulated mechanical procedures of the Roman capital's monetary workshops.

Obverse Iconography and Modeling

The obverse displays a refined right-facing portrait bust of Agrippina the Elder. Her hair is rendered in classic Julio-Claudian fashion, parted cleanly along the crown and drawn softly down the sides of the head in waves, gathered at the nape into a long plaited queue that falls gracefully along the neck, with a loose tress brushing each shoulder. The physiognomy is dignified, featuring the straight nasal bridge, firm chin, and restrained expression typical of official portraits created for Julio-Claudian dynasts. The depiction draws directly upon metropolitan statuary types erected to honor the daughter of Agrippa and Julia. Unlike contemporary portraiture of living empresses or princesses, the image conveys a timeless, idealized serenity appropriate for a post-mortem memorial tribute. The portrait is framed by a complete circular inscription running counterclockwise or clockwise along the outer beaded border, fully integrating the figure into the imperial nomenclature.

Reverse Design: The Honorific Carpentum

The reverse of the sestertius features an elaborate two-wheeled carriage, known in Latin as a carpentum, shown facing right and pulled by a pair of mules. The carpentum was a traditional covered ceremonial vehicle reserved by ancient custom and senatorial decree for Roman matrons of the highest distinction, as well as for the transport of sacred images (thesaura) during official public games. The vehicle depicted on this issue is richly ornamented: the sides of the carriage body are articulated with carved panels, frequently exhibiting decorative figures, winged genii, or floral motifs, while the arched roof is supported by corner figures or caryatids and covered with draped textile or ornate paneling. Suetonius records that Caligula arranged for his mother's effigy to be carried through the Circus Maximus in a carpentum during the ludi circenses, ensuring that her memory was continually honored alongside the gods. The vehicle is shown with heavy spoked wheels and ornate harness straps connecting the mules, creating an architectural and vehicular composition rarely matched on early imperial aes.

Epigraphy and Inscriptional Content

The legends on both sides of RIC I (second edition) Gaius/Caligula 55 articulate the hereditary and legal foundations of the issue. The obverse legend reads AGRIPPINA M F MAT C CAESARIS AVGVSTI, an abbreviated formulation expanding to 'Agrippina, Marci Filia, Mater Gai Caesaris Augusti' (Agrippina, daughter of Marcus [Agrippa], mother of Gaius Caesar Augustus). This inscription carefully identifies her paternal descent from Augustus's chief lieutenant Marcus Vipsanius Agrippa while simultaneously stating her role as mother of the ruling princeps. The reverse legend is divided between the upper field and vehicle surroundings, reading S P Q R MEMORIAE AGRIPPINAE, expanding to 'Senatus Populusque Romanus, Memoriae Agrippinae' (The Senate and the Roman People, to the Memory of Agrippina). This phrasing formally attributes the honors to the combined sovereign bodies of the Roman state, casting the rehabilitation of Agrippina not merely as private filial affection, but as an official decree of public restitution.

Typology and Chronological Classification

Within the typology established by C. H. V. Sutherland in the revised second edition of Roman Imperial Coinage Volume I, type 55 designates the standard Rome-mint sestertius bearing the mule-drawn carpentum right without an obverse S C. Chronologically, this type was inaugurated early in Caligula's principate, most plausibly between AD 37 and 40, directly following the return of Agrippina's ashes to Rome in late spring or summer of AD 37. Numismatists have noted that while the initial emission belongs strictly to Caligula's reign, the popularity and iconographic utility of the type led to its prolonged circulation. Under Claudius (AD 41 to 54), Agrippina's brother-in-law, a closely related series was struck (RIC I [second edition] Claudius 102), retaining the identical obverse legend and reverse carpentum design, occasionally distinguished by minute stylistic changes in portrait rendering or subsequent countermarking. Type 55 under Caligula represents the definitive primary emission that established the carpentum composition as an enduring numismatic monument.

Circulation, Countermarks, and Survival

Upon release from the Rome mint, sestertii of RIC I (second edition) Gaius/Caligula 55 circulated extensively throughout the Italian peninsula and entered monetary streams across the western provinces, including Gaul, the Rhineland, and Hispania. As substantial orichalcum pieces, they experienced decades of active use. In the reign of Claudius and during the civil wars of AD 68 to 69, many surviving specimens were countermarked by legionary authorities or regional administrative bodies (bearing marks such as TIAV, NCAPR, or provincial stamps), testifying to their prolonged utility in trade long after Caligula's assassination and subsequent senatorial condemnation. While Caligula's own portrait bronzes were frequently melted down or defaced following his death, the coins dedicated to his revered mother Agrippina the Elder were generally spared from damnatio memoriae due to the profound respect the Roman public and senate maintained for Germanicus and his family.

References

1. Coins of the Roman Empire in the British Museum, Volume I: Augustus to Vitellius. pp. 159-160, nos. 81-87
2. Online Coins of the Roman Empire: RIC I (second edition) Gaius/Caligula 55. ric.1(2).gai.55
3. The Roman Imperial Coinage, Volume I: From 31 BC to AD 69 (Revised Edition). pp. 112, no. 55
4. De Vita Caesarum: Gaius Caligula. Book IV, Chapter 15