Caesar Augustus Germanicus (b. A.D. 12, d. A.D. 41,
emperor A.D. 37-41) represents a turning point in
the early history of the Principate. Unfortunately,
his is the most poorly documented reign of the
Julio-Claudian dynasty. The literary sources for
these four years are meager, frequently anecdotal,
and universally hostile.[] As a result, not only
are many of the events of the reign unclear, but
Gaius himself appears more as a caricature than a
real person, a crazed megalomaniac given to
capricious cruelty and harebrained schemes. Although
some headway can be made in disentangling truth from
embellishment, the true character of the youthful
emperor will forever elude us.
Gaius's Early Life and Reign
Gaius was born on 31 August, A.D. 12, probably at
the Julio-Claudian resort of Antium (modern Anzio),
the third of six children born to Augustus's adopted
grandson, Germanicus, and Augustus's granddaughter,
Agrippina. As a baby he accompanied his parents on
military campaigns in the north and was shown to the
troops wearing a miniature soldier's outfit,
including the hob-nailed sandal called caliga,
whence the nickname by which posterity remembers
him.[] His childhood was not a happy one, spent
amid an atmosphere of paranoia, suspicion, and
murder. Instability within the Julio-Claudian house,
generated by uncertainty over the succession, led to
a series of personal tragedies. When his father died
under suspicious circumstances on 10 October A.D.
19, relations between his mother and his
grand-uncle, the emperor Tiberius, deteriorated
irretrievably, and the adolescent Gaius was sent to
live first with his great-grandmother Livia in A.D.
27 and then, following Livia's death two years
later, with his grandmother Antonia. Shortly before
the fall of Tiberius's Praetorian Prefect, Sejanus,
in A.D. 31 he was summoned to join Tiberius at his
villa on Capri, where he remained until his
accession in A.D. 37. In the interim, his two
brothers and his mother suffered demotion and,
eventually, violent death. Throughout these years,
the only position of administrative responsibility
Gaius held was an honorary quaestorship in A.D. 33.
When Tiberius died on 16 March A.D. 37, Gaius was in
a perfect position to assume power, despite the
obstacle of Tiberius's will, which named him and his
cousin Tiberius Gemellus joint heirs. (Gemellus's
life was shortened considerably by this bequest,
since Gaius ordered him killed within a matter of
months.) Backed by the Praetorian Prefect Q.
Sutorius Macro, Gaius asserted his dominance. He had
Tiberius's will declared null and void on grounds of
insanity, accepted the powers of the Principate as
conferred by the Senate, and entered Rome on 28
March amid scenes of wild rejoicing. His first acts
were generous in spirit: he paid Tiberius's bequests
and gave a cash bonus to the Praetorian Guard, the
first recorded donativum to troops in imperial
history. He honored his father and other dead
relatives and publicly destroyed Tiberius's personal
papers, which no doubt implicated many of the Roman
elite in the destruction of Gaius's immediate
family. Finally, he recalled exiles and reimbursed
those wronged by the imperial tax system []. His
popularity was immense. Yet within four years he lay
in a bloody heap in a palace corridor, murdered by
officers of the very guard entrusted to protect him.
What went wrong?
The ancient sources are practically unanimous as to
the cause of Gaius's downfall: he was insane. The
writers differ as to how this condition came about,
but all agree that after his good start Gaius began
to behave in an openly autocratic manner, even a
crazed one. [] Outlandish stories cluster about
the raving emperor, illustrating his excessive
cruelty, immoral sexual escapades, or disrespect
toward tradition and the Senate. The sources
describe his incestuous relations with his sisters,
laughable military campaigns in the north, the
building of a pontoon bridge across the Bay at Baiae,
and the plan to make his horse a consul. []
Modern scholars have pored over these incidents and
come up with a variety of explanations: Gaius
suffered from an illness; he was misunderstood; he
was corrupted by power; or, accepting the ancient
evidence, they conclude that he was mad.[]
However, appreciating the nature of the ancient
sources is crucial when approaching this issue.
Their unanimous hostility renders their testimony
suspect, especially since Gaius's reported behavior
fits remarkably well with that of the ancient
tyrant, a literary type enshrined in Greco-Roman
tradition centuries before his reign. Further, the
only eye-witness account of Gaius's behavior,
Philo's Embassy to Gaius, offers little evidence of
outright insanity, despite the antagonism of the
author, whom Gaius treated with the utmost
disrespect. Rather, he comes across as aloof,
arrogant, egotistical, and cuttingly witty -- but
not insane. The best explanation both for Gaius's
behavior and the subsequent hostility of the sources
is that he was an inexperienced young man thrust
into a position of unlimited power, the true nature
of which had been carefully disguised by its
founder, Augustus. Gaius, however, saw through the
disguise and began to act accordingly. This, coupled
with his troubled upbringing and almost complete
lack of tact led to behavior that struck his
contemporaries as extreme, even insane.
Gaius and the Empire
Gaius's reign is too short, and the surviving
ancient accounts too sensationalized, for any
serious policies of his to be discerned. During his
reign, Mauretania was annexed and reorganized into
two provinces, Herod Agrippa was appointed to a
kingdom in Palestine, and severe riots took place in
Alexandria between Jews and Greeks. These events are
largely overlooked in the sources, since they offer
slim pickings for sensational stories of madness.
[] Two other episodes, however, garner greater
attention: Gaius's military activities on the
northern frontier, and his vehement demand for
divine honors. His military activities are portrayed
as ludicrous, with Gauls dressed up as Germans at
his triumph and Roman troops ordered to collect
sea-shells as "spoils of the sea." Modern scholars
have attempted to make sense of these events in
various ways. The most reasonable suggestion is that
Gaius went north to earn military glory and
discovered there a nascent conspiracy under the
commander of the Upper German legions, Cn. Lentulus
Gaetulicus. The subsequent events are shrouded in
uncertainty, but it is known that Gaetulicus and
Gaius's brother-in-law, M. Aemilius Lepidus, were
executed and Gaius's two surviving sisters,
implicated in the plot, suffered exile. []
Gaius's enthusiasm for divine honors for himself and
his favorite sister, Drusilla (who died suddenly in
A.D. 38 and was deified), is presented in the
sources as another clear sign of his madness, but it
may be no more than the young autocrat tactlessly
pushing the limits of the imperial cult, already
established under Augustus. Gaius's excess in this
regard is best illustrated by his order that a
statue of him be erected in the Temple at Jerusalem.
Only the delaying tactics of the Syrian governor, P.
Petronius, and the intervention of Herod Agrippa
prevented riots and a potential uprising in
Conspiracy and Assassination
The conspiracy that ended Gaius's life was hatched
among the officers of the Praetorian Guard,
apparently for purely personal reasons. It appears
also to have had the support of some senators and an
imperial freedman. [] As with conspiracies in
general, there are suspicions that the plot was more
broad-based than the sources intimate, and it may
even have enjoyed the support of the next emperor
Claudius, but these propositions are not provable on
available evidence. On 24 January A.D. 41 the
praetorian tribune Cassius Chaerea and other
guardsmen caught Gaius alone in a secluded palace
corridor and cut him down. He was 28 years old and
had ruled three years and ten months. []
Whatever damage Tiberius's later years had done to
the carefully crafted political edifice created by
Augustus, Gaius multiplied it a hundredfold. When he
came to power in A.D. 37 Gaius had no administrative
experience beyond his honorary quaestorship, and had
spent an unhappy early life far from the public eye.
He appears, once in power, to have realized the
boundless scope of his authority and acted
accordingly. For the elite, this situation proved
intolerable and ensured the blackening of Caligula's
name in the historical record they would dictate.
The sensational and hostile nature of that record,
however, should in no way trivialize Gaius's
importance. His reign highlighted an inherent
weakness in the Augustan Principate, now openly
revealed for what it was -- a raw monarchy in which
only the self-discipline of the incumbent acted as a
restraint on his behavior. That the only means of
retiring the wayward princeps was murder marked
another important revelation: Roman emperors could
not relinquish their powers without simultaneously
relinquishing their lives.
The bibliography on Gaius is far too vast for
comprehensive citation here. Most of the ancient
material can be found in Gelzer and Smallwood. Ample
reference to relevant secondary works is made in
Barrett, Caligula (319-28) and Hurley (219-30). The
works listed below are therefore either the main
treatments of Gaius or are directly pertinent to the
issues discussed in the entry above.
- Balsdon, J.P.V.D. The Emperor Gaius. Oxford, 1934.
- ________. "The Principates of Tiberius and Gaius."
ANRW 2.2 (1975): 86-94.
- Barrett, A.A. Caligula: The Corruption of Power. New
- ________. Agrippina. Sex, Power, and Politics in the
Early Empire. New Haven, 1996.
- Benediktson, D.T. "Caligula's Madness: Madness or
Interictal Temporal Lobe Epilepsy?" Classical World
82 (1988-89), 370-5.
- Bicknell, P. "The Emperor Gaius' Military Activities
in AD 40." Historia 17 (1968): 496-505.
- Bilde, P. "The Roman Emperor Gaius (Caligula)'s
Attempt to Erect his Statue in the Temple of
Jerusalem." STh 32 (1978): 67-93.
- Boschung, D. Die Bildnisse des Caligula. Berlin,
- Charlesworth, M.P. "The Tradition About Caligula"
Cambridge Historical Journal 4 (1933): 105-119.
- Davies, R.W. "The Abortive Invasion of Britain by
Gaius." Historia 15 (1966): 124-28.
- D'Ecré, F. "La mort de Germanicus et les poisons de
Caligula." Janus 56 (1969): 123-48.
- Ferrill, A. Caligula, Emperor of Rome. London, 1991.
- Gelzer, M. "Iulius Caligula." Real-Enzyclopädie
- Grant, M. The Roman Emperors. A Biographical Guide
to the Rulers of Imperial Rome 31 BC - AD 476 (New
York, 1985), 25-28.
- Hurley, D.W. "Gaius Caligula in the Germanicus
Tradition." American Journal of Philology 110
- ________. An Historical and Historiographical
Commentary on Suetonius' Life of C. Caligula.
- Jerome, T.S. "The Historical Tradition About Gaius,"
in id., Aspects of the Study of Roman History. New
- Katz, R.S. "The Illness of Caligula." Classical
World 65 (1971-72): 223-5
- McGinn, T.A.J. "Caligula's Brothel on the Palatine,"
EMC 42 (1998): 95-107.
- Massaro, V. and I. Montgomery. "Gaius: Mad Bad, Ill
or All Three?" Latomus 37 (1978): 894-909
- ________. "Gaius (Caligula) Doth Murder Sleep."
Latomus 38 (1979): 699-700.
- Maurer, J. A. A Commentary on C. Suetoni Tranquilli,
Vita C. Caligulae Caesaris, Chapters I-XXI.
- Morgan, M.G. "Caligula's Illness Again." Classical
World 66 (1972-73): 327-9
- Philips, E.J. "The Emperor Gaius' Abortive Invasion
of Britain." Historia 19 (1970): 369-74.
- Simpson, C. J. "The 'Conspiracy' of AD 39." In
Studies in Latin Literature and Roman History II,
edited by C. Deroux, 347-66. Brussels, 1980.
- Smallwood, E.M. (ed.). Documents Illustrating the
Principates of Gaius, Claudius and Nero. Cambridge.
- Wardle, D. Suetonius' Life of Caligula: A
Commentary. Brussels, 1994.
- Woods, D. "Caligula's Seashells." Greece and Rome 47
- Wood, S. "Diva Drusilla Panthea and the Sisters of
Caligula." AJA 99 (1995): 457-82.
[] The main ancient sources for Gaius's reign
are: Suet. Gaius; Dio 59; Philo In Flaccum and
Legatio ad Gaium; Jos. AJ 19.1-211. Tacitus's
account of the reign is lost. However, he makes
occasional references to Gaius in the extant
portions of his works, as does Seneca. All of these
sources have reason to be hostile to Gaius's memory:
Seneca's style was roundly abused by the emperor
(Suet. Gaius 53.2; Dio 59.19.7-8); Philo and
Josephus, as Jews, resented Gaius's blasphemous
demands for divinity that almost roused Palestine to
rebellion (see above, Gaius and the Empire); and the
later sources inherited a tradition about Gaius that
can be shown to be biased and exaggerated, cf.
Charlesworth, "The Tradition about Gaius." Besides
these literary sources, inscriptions and coins also
offer some information, see Smallwood, Documents
[] Tac. Ann. 1.41.3; Suet. Gaius 9.1.
[] Death of Germanicus and aftermath: Tac. Ann.
2.69-3.19; Gaius with Livia, Antonia, and Tiberius:
Tac. Ann. 6.20.1; Suet. Gaius 10.1, 23.2; fate of
Agrippina: Tac. Ann. 5.3.2 - 5.5.2, 6.25.1; and of
Nero and Drusus Caesar: Tac. Ann. 5.3.2, 6.23.4-5,
Suet. Tib. 54, Gaius 7; Gaius's quaestorship: Dio
58.23.1. For the alleged involvement of Gaius in his
father's death, see D'Ecré, "La mort de Germanicus."
[] Early reign and first acts: Suet. Gaius 13-16;
Philo Leg. 8-13; Dio 59.2-3. Macro's full name:
Smallwood, Documents Illustrating, no. 254. Date of
Gaius's arrival in Rome: Acta Fratrum Arvalium
(Smallwood, Documents Illustrating, no. 3.15-17).
Gemellus: Suet. Gaius 14.1, 15.2, 23.3; Dio
59.1.2-3, 59.8.1-2; Philo Leg. 23-31.
[] Seneca, without explanation, believes he went
mad (Brev. 18.5-6; Helv. 10.4; Tranqu. 14.5; Ben.
7.11.2). Josephus also thinks that Gaius went mad
but alludes to a love-potion administered by his
wife Caesonia as the cause (AJ 19.193), apparently
after two years of good rule (AJ 18.256). Philo
blames an illness in the fall of A.D. 37 (Leg.
14-22). Suetonius mentions simply a "brain sickness"
(valitudo mentis; Gaius 51.1). Dio thinks that
faults of character led to a deterioration in his
behavior (59.3-4). Surviving references suggest that
Tacitus thought Gaius at least of troubled and
impulsive mind, which is not the same thing as
crazed (Agr. 13.2; Ann. 6.20.1, 6.45.5, 13.3.6; Hist.
[] Incest: Suet. Gaius 24.1; Dio 59.3.6; Jos. AJ
19.204. Military campaigns: Tac. Hist. 4.15.3,
Germania 37.5, Suet. Gaius 43-46, Dio 59.21.1-3.
Bridge at Baiae: Suet. Gaius 19; Dio 59.17; Jos. AJ
19.5-6. Horse as consul: Suet. Gaius 55.3; Dio
59.14.7; His alleged setting up of a brothel in the
palace may contain a kernel of truth, even if the
story is much embellished, see T.A.J. McGinn,
"Caligula's Brothel on the Palatine," EMC 42 (1998):
[] Alcoholism: Jerome, "Historical Tradition";
hyperthyroidism/thyrotoxicos: Katz, "Illness of
Caligula"; mania: Massaro and Montgomery, "Gaius:
Mad, Bad, Ill or All Three" and "Gaius (Caligula)
Doth Murder Sleep"; epilepsy: Benediktson,
"Caligula's Madness." Morgan ("Caligula's Illness
Again") makes some astute observations on the
weakness of the medical approach as a whole. He
points out that the ancient concept of physiognomy
-- that people's characters are manifest in their
appearance -- makes any diagnosis highly suspect. In
fact, all such medical explanations are doomed to
failure. The sources simply cannot be trusted, and
diagnosing a patient 2,000 years dead is, at best, a
stretch. Balsdon (The Emperor Gaius) argued that
Gaius was misunderstood and attempted to offer
rational explanations for all of his apparently
deranged antics. A useful summary and critique of
"madness" theories is to be found in Barrett,
Caligula, 213-41. For a recent acceptance of the
madness thesis, cf. Ferrill, Caligula, Emperor of
[] Mauretania: Dio 59.25.1; see also Barrett,
Caligula, 115-20. Agrippa: Jos. AJ 18.228-37; Phil
Leg. 324-26; see also E. M. Smallwood, The Jews
under Roman Rule (Leiden, 1976), 187-200.
Alexandrian riots: Philo Flacc and Leg.
[] Fake Germans in triumph: Suet. Gaius 47.
Military campaigns: see above, note . For modern
rationalizations of these campaigns, cf., e.g.,
Bicknell, "Military Activities"; Davies, "Abortive
Invasion"; Philips, "Abortive Invasion"; Barrett,
Caligula, 125-39, and Woods, "Caligula's
Seashells.". Execution of Gaetulicus and exile of
sisters: the Gaetulicus affair is ably assessed in
Barrett, Caligula, 91-113, and id. Agrippina, 60-70;
for a contrasting view, see Simpson, "The
'Conspiracy' of AD 39."
[] The Jerusalem affair is described most fully
by Josephus (AJ 18.261-309; BJ 2.184-203) and Philo
(Leg. 188, 198-348). Thorough modern assessments can
be found in Barrett, Caligula, 188-91, cf. 140-53
(on Gaius's demand for divine honours, which Barrett
argues are exaggerated by the sources); Bilde
"Statue in the Temple"; and Smallwood, Jews (above,
note ), 174-80. Drusilla: Suet. Gaius 24.2-3; Dio
59.11; Smallwood, Documents Illustrating, nos
5.12-15, 11, 128, 401.12; Wood, "Diva Drusilla."
[] The named Praetorian conspirators include
three tribunes -- Cassius Chaerea (Suet. Gaius 56.2;
Dio 59.29.1; Sen. Const. 18.3; Jos. AJ 19.18, 21,
28-37); Cornelius Sabinus (Suet. Gaius 58.2; Dio
59.29.1; Jos. AJ 19.46, 48, 261); Papinius (Jos. AJ
19.37) -- and the Prefect M. Arrecinus Clemens (Jos.
AJ 19.37-46). Senators associated with the plot are
M. Annius Vinicianus (Jos. AJ 19.18, 20, 49-51), M.
Valerius Asiaticus (Tac. Ann. 11.1.2), Cluvius Rufus
and L. Nonius Asprenas (Jos. AJ 19.91-92, 98).
Gaius's freedman Callistus is also a named
participant (Tac. Ann. 11.29.1; Dio 29.29.1; Jos. AJ
[] The possible involvement of Claudius in the
plot is assessed by B. Levick, Claudius (New Haven,
1990), 33-39. The fullest account of the
assassination is that of Josephus (AJ 19.70-113),
with more summary accounts found in Suetonius (Gaius
58) and the epitome of Dio (59.29.5-7).