Bronze Sestertii of Caligula (37-41 CE)

Historical Context

Caligula, formally Gaius Caesar Augustus Germanicus, ruled in AD 37-41. His sestertii combine the emperor's titles with dynastic, civic, military and religious imagery. A survey of the denomination must therefore range beyond the three-sisters reverse, even though that design is especially distinctive. The same ruler's name occurs with different obverse subjects and reverse compositions.

The sisters are Agrippina the Younger, Drusilla and Julia Livilla. They are not three independent issuing rulers, and Agrippina the Younger must be distinguished from their mother, Agrippina the Elder. The naming of the sisters brings the imperial family into the coin's public message. It does not make the coin a joint imperial issue or a posthumous coin of Caligula.

Susan Wood interprets these honors in terms of dynastic continuity and the potential of the sisters to bear Julian descendants. Her argument is a scholarly interpretation of coins, sculpture and literary evidence, not a literal statement written on the reverse. It offers a framework more precise than treating the imagery simply as an illustration of hostile anecdotes about the emperor. The denomination also presents civic gratitude, an address to troops and sacrifice honoring Augustus, demonstrating the range of themes used during the reign.

Obverse Iconographic Composition

The portrait families include a laureate head of Caligula facing left. Laurel is a wreath, so this is not a bare-headed portrait. The emperor's head and surrounding titles identify him while the reverse may be occupied by relatives, troops or an inscription rather than another portrait.

Not all sestertii in this survey place the emperor's head on the obverse. In the temple-sacrifice family, a veiled and draped Pietas is seated left, holding a patera, or shallow ritual dish. A small figure forms part of the seat arrangement. The inscription PIETAS identifies the personification; her appearance should not be relabeled a portrait of one of Caligula's sisters without further evidence.

The contrast between an imperial portrait and a personification is part of the typology, not merely a difference in artistic execution. The emperor can remain the issuing authority even where the obverse displays Pietas. On that family the reverse, rather than the obverse, shows Caligula taking part in sacrifice. Classification must account for both faces instead of assuming that every obverse necessarily portrays the named ruler.

Obverse Epigraphy and Inscriptions

One documented portrait formula reads C CAESAR AVG GERMANICVS PON M TR POT: Gaius Caesar Augustus Germanicus, chief priest, with tribunician power. C abbreviates the personal name Gaius; AVG is Augustus, and PON M abbreviates pontifex maximus. The wording should be transcribed as it appears rather than expanded into a different die legend.

A later checked Pietas type reads C CAESAR DIVI AVG PRON AVG P M TR P III P P. DIVI AVG PRON presents Gaius as the great-grandson of the deified Augustus. TR P III records tribunician power for the third time, and P P means pater patriae, father of the country. The documented example is dated AD 39-40. This is evidence for a particular formula, not proof of a complete four-emission production schedule.

Titles provide chronological information but their position and abbreviation can vary. A bare TR POT and a numbered TR P III should not be treated as interchangeable transcriptions. Nor should an absent or illegible numeral be supplied simply because a reverse resembles a dated parallel. The PIETAS label belongs to the seated personification and is distinct from the emperor's encircling titles.

Reverse Iconographic Composition

Four documented reverse families illustrate the breadth of the sestertius series.

Three sisters: Three draped women stand together and are named AGRIPPINA DRVSILLA IVLIA. Cornucopiae and other attributes associate the group with personified benefits and dynastic well-being. The precise allegorical associations are interpretations of attributes; the named women themselves are securely distinguished by the inscription.

Military address: ADLOCVT COH identifies an address to the cohorts. The composition relates the emperor to a body of troops. It is a separate family from the sisters design, not an alternative reading of it.

Civic wreath: An oak wreath encloses the words S P Q R P P OB CIVES SERVATOS. Here an inscription rather than a narrative scene occupies the center. The design associates civic gratitude with the emperor.

Temple sacrifice: Caligula, veiled and togate, sacrifices at an altar before a garlanded temple with six columns. Attendants and a bull form part of the scene. DIVO AVG identifies the dedication to deified Augustus. The architecture is an image in a ritual composition, not a measured plan from which the building's dimensions can be reconstructed.

Reverse Epigraphy and Inscriptions

The three-sisters formula AGRIPPINA DRVSILLA IVLIA names the women; S C is placed below them. S C conventionally expands as senatus consulto, 'by decree of the Senate'. The letters should be read as part of the type's inscription, not as an independent test of denomination or a complete description of mint administration.

ADLOCVT COH abbreviates adlocutio cohortium, 'address to the cohorts'. The words identify the action and military audience. They do not themselves give the date, size of a donative or source of the money used for a distribution. Such financial claims require evidence beyond the legend.

S P Q R P P OB CIVES SERVATOS can be expanded as senatus populusque Romanus, patri patriae, ob cives servatos: 'the Senate and Roman People, to the father of the country, for saving citizens'. Its civic vocabulary differs from the military-address wording even when the obverse titles resemble one another.

DIVO AVG means 'to the deified Augustus'. It refers to the earlier emperor honored by the sacrifice, not to the deification of Gaius. The accompanying S C and the separate PIETAS label on the obverse contribute different information. Combining all these words into a single continuous legend would erase the organization of the two designs.

Typology and Documented Variants

The selected families are documented across more than one part of Caligula's reign, without claiming an exhaustive list of dies or emissions:

• Three sisters, AD 37-38: Laureate portrait left and three named standing women; the checked university catalogue cites revised RIC I Gaius 33. The date pertains to this family, not to the whole sestertius series.
• Civic wreath, AD 37-38: Portrait of the emperor paired with S P Q R P P OB CIVES SERVATOS inside an oak wreath. This is independently documented institutional evidence for a non-narrative reverse.
• Military address, catalogued AD 37-41: A Caligula sestertius with ADLOCVT COH establishes the family without requiring an unverified individual catalogue number.
• Pietas and temple sacrifice, AD 39-40: Seated Pietas with the third tribunician title, paired with sacrifice to Augustus. The checked university record cites revised RIC I Gaius 44.

These are type-family comparisons, not exact attributions of every coin sharing one motif. Bust details, full legends, reverse arrangements and catalogue edition must agree before a number can be transferred. Coins portraying Agrippina the Elder or other relatives under Gaius are related dynastic material, but are not silently substituted for the named Caligula series.

Scholarly Debates and Attribution Limitations

Several distinctions constrain interpretation. First, the sisters' names establish their identities more securely than a proposed one-to-one equation with divine personifications. Wood's dynastic reading and the associations suggested by their attributes are useful interpretations, not proof that each attribute always had one fixed meaning for every viewer.

Second, Drusilla's later deification does not make every appearance of her a DIVA issue. The three-sisters legend names DRVSILLA without that title. A claim that a particular later-dated combination is impossible, altered or modern requires an examined catalogue discussion and physical evidence; family chronology alone cannot authenticate or condemn a coin.

Third, epigraphic differences should not be transformed into a complete fiscal history. An abbreviated military-address legend cannot establish whether a special treasury, private purse or donative funded production. Similarly, S C does not, on its own, prove an autonomous senatorial mint.

Finally, the selected dates and type references do not establish a production hiatus in a missing tribunician year, exact output or a uniform die axis. Such conclusions need a defined corpus or die study. This survey presents documented designs across the reign, not an exhaustive emission sequence, and makes no universal weight, diameter or alloy-percentage claim.

References

1. C. H. V. Sutherland, The Roman Imperial Coinage I, revised edition (1984). BnF bibliographic record; From 31 BC to AD 69; metadata, not an unread emission study
2. Lawrence University: Gaius sestertius with Pietas and temple sacrifice. Catalogue 71; AD 39-40; RIC I revised edition 44
3. Susan Wood, Diva Drusilla Panthea and the Sisters of Caligula. American Journal of Archaeology 99.3 (1995), pp. 457-482; publisher abstract
4. ANU Classics Museum: Sestertius of Gaius (Caligula). 1974.05; brass sestertius AD 37-38; three sisters; revised RIC I 33
5. Metropolitan Museum of Art: Bronze sestertius of Gaius. 99.35.448; AD 37-38; civic wreath and inscriptions
6. MFA Houston: Sestertius of Caligula with ADLOCVT COH. 2004.1353; AD 37-41; inscription evidence for the address family