Caligula was propelled into the principate because of the popularity of his father, Germanicus, and the relief felt by the end of the austerity of Tiberius’ reign. However, he was a remote figure, not having lived in public view for several years. News of Tiberius’ death was at first treated with suspicion, as if it were a test of loyalty, but when it was confirmed people reacted with jubilation. Many thought he should be thrown down the Gemonian stairs or even pitched into the Tiber. "Tiberius im Tiberim" became a popular slogan (Tib. 75; AJ 18.225-33).

Macro lost no time in sending out instructions to provincial governors and army commanders on the succession. One of these went to Lucius Vitellius, who was governor of Syria and, without hesitation, administered the oath of loyalty to Caligula. Macro was in Rome by March 18 to deliver two letters from Caligula. One of them went to the city prefect, asking, since Caligula did not yet have the power to command, that Agrippa be release from prison into house arrest. In due time, Agrippa was freed but many other convicted criminals went to their execution since their jailers were fearful not to carry out the law, despite a moratorium voted by the Senate (Tib. 75.2; AJ 18.234). The other letter was an official report to the Senate on Tiberius’ death. The letter asked that Tiberius be granted the same divine honors as Augustus, but the senators never brought the matter to a vote and Caligula, his piety demonstrated, never brought up the matter again (Dio 59.3.7).

There followed a series of moves by Macro to secure Caligula as the sole emperor. Tiberius’ will made Caligula and Gemellus joint heirs but, despite the political implications of the document, neither had been clearly marked as heir to the empire. After consulting legal experts, Macro chose to have the will nullified. To annul the will meant that no one would succeed Tiberius and his property would be divided between all of his descendants. Caligula eventually inherited Tiberius’ property by virtue of his position as princeps, setting the precedent that not only would a new emperor acquire the political power of his predecessor but imperial property as well (Cal. 14.1).

Macro had already bought the loyalty of the Praetorians and the army (Caligula distributed 2,000 sesterces apiece to the guards, twice what Tiberius had paid), so the Senate may have felt they needed to acquiesce in the formal granting of power. [1]   Caligula was young and inexperienced and might be easily manipulated. According to the Arval records, Caligula was acclaimed imperator on March 18. The Senate and the army traditionally had the right to acclaim a victorious general imperator but Caligula had won no such victory. Rather, the acclimation by the Senate confirmed the earlier acknowledgement by the Praetorian’s at Misenum (Leg. 231; AJ 18.124). Caligula’s accession had gone off without incident. He began a stately procession from Misenum accompanied by soldiers, escorting the body of Tiberius. As the procession made its way, people came out in throngs to see the new emperor calling him pet names like ’chick’, "star’ and ‘baby’ (Cal. 13). The ecstatic reaction spread throughout the empire and a golden age was declared with celebrations from all classes of people. In Jerusalem and Alexandria, the Jews offered lavish sacrifices in honor of the new emperor (Leg. 10-13, 232, 356).

Caligula arrived in Rome on March 28 and probably appeared before the Senate the same day. [2]  Under Macro’s guidance, he showed maximum deference to the senators. The meeting was an unparalleled event attended by equestrians and ordinary people. Goodwill prevailed and the Senate proceeded to grant Caligula all of the powers held by Augustus at a stroke (Cal. 14.1; Dio 59.3.1-2, 6.1). The senatorial resolution that granted the powers has not survived but it was probably similar to the lex imperii of Vespasian. The careful balance of power that Caligula’s predecessors had maintained with the Senate had ended, as did the sanctioned powers that Augustus had exercised by virtue of his authority (auctoritas). Caligula’s later boast that he had "every power over every person" was precisely what the Senate had done; his power was unchecked (Cal. 22.1; Leg. 119). In addition, the Senate granted titles appropriate to Caligula’s new position. He became: Gaius Julius Caesar Germanicus. The title Augustus was also granted, allowing the new emperor the moral and political authority associated with the first princeps. Tiberius had declined this title and only used it when dealing with foreign kings (Tib. 26.2; Dio 57.2.1). Caligula also became Pontifex Maximus, the chief interpretor of sacred law, (after a short period of time PM appears on his earliest coins) and he assumed the title Pater Patriae after a short postponement (Dio 59.6.1). Suetonius says that Caligula granted himself additional titles such as Pius, Castorum Filius (son of the camp), Pater Exercituum (father of the armies) and Optimus Maximus Caesar (Cal. 22.1). There is no other evidence that he assumed any of these titles, however, Caligula would have wanted to capitalize on his childhood popularity among the soldiers by referring to himself as Castorum Filius. It equally makes sense that he would use Pater Exercituum during his German campaign.

Tiberius’ body had been left outside Rome for security reasons and was brought into the city on March 29. A few days passed while preparations for the funeral were carried out, which occurred on April 3. [3] This is contrary to Dio’s suggestion that Caligula brought Tiberius’ body into the city under cover of darkness and had a hasty funeral (59.3.7-8). Caligula delivered a tear-filled eulogy. Following the cremation, Tiberius’ ashes were placed in the mausoleum of Augustus and his birthday received official celebration in 40 (Cal. 15.1; Dio 59.3.8; AJ 18.236). Caligula paid Tiberius’ legacies, including the unpaid bequests from Livia’s will.

While living under the watchful eye of Tiberius on Capri, Caligula had shown no inclination to intercede on behalf of his mother and brother. Now that he was emperor, he could safely take on the role of dutiful son and journeyed to Pontia and Pandateria to collect their ashes. It was not an easy task since Nero’s remains were deliberately scattered and Caligula’s passage to the islands was stormy, which made his devotion seem even greater. He returned to Rome with the urns containing Nero’s and Agrippina’s ashes, carried on biers by equestrians. They were interred in the mausoleum of Augustus, even though Agrippina had been declared an enemy of the state by Tiberius. The ceremony was carried out when it could have the maximum effect: during the crowded middle of the day. There was no trace of Drusus’ remains so a cenotaph was erected (Tib. 54.2, Cal. 15.1; Dio 59.3.5). Honors were heaped on Caligula’s parents. The Arval Brethren sacrificed on their birthdays and September was renamed Germanicus. Games were established in Agrippina’s memory and a carpentum carried her image in a procession to the circus.

The shadow of Marco was behind these highly popular gestures. Philo mentions that the Prefect would wake the emperor if he fell asleep at dinner parties, would curb him if he became too boisterous and reminded him to behave within his station. Suetonius says Caligula insisted Marco be present when his grandmother Antonia requested a private interview (Leg. 41-46; Cal. 23.2). Caligula granted Antonia the rights once enjoyed by Livia, including the privileges of the Vestal Virgins and the title Augusta. Although Caligula honored his grandmother, ancient sources say he became irritated by her interference (Cal. 29.1; AJ 18.236). Antonia died on May 1, 37, at the age of seventy-three. Caligula is said to have driven her to suicide but this is hardly possible since, having arrived in Rome on March 28, he was absent almost all of April collecting the ashes of his mother and brother. Antonia died while Caligula was practicing pietas, so a slight to his grandmother would be out of the question (Cal. 23.2; Dio 59.3.6). [4]

Caligula scored a diplomatic success at the start of his reign with Parthia. Early in 37, the Parthian king Artabanus was reportedly planning to invade Syria. The governor, Vitellius, acting with great courage, moved his legions to the Euphrates and overawed the king. The king gave up any thought of hostilities and an amicable agreement was reached where Artabanus sent his son Darius to Rome as a hostage. The king even paid homage to the Roman standards. Part of the reason for Artabanus’ cooperation was the regard and affection he held for Germanicus, which had been transferred to his son. (AJ 18.102; Cal.14.3, Vit. 2.4; Dio 59.27.3). Caligula sensibly allowed himself to be guided by Vitellius in setting his Parthian policy. Although details of the agreement with Artabanus are not known it may have included the removal of the king of Armenia, Mithradates, who was recalled to Rome where he was imprisoned for unknown reasons. The removal of Mithridates cannot be accurately dated. Seneca couples his name with Ptolemy so Mithridates could have been recalled in late 39 or 40. He may have been lax in his administration of Armenia which required his removal. Claudius restored Mithridates to his throne and he remained in power until murdered in 51 by his nephew Radamistus (Ann. 11.8.1; Dio 60.8.1; Sen. Tranq 11.12). [6]

We are told that Caligula abolished the charge of maiestas, which had forced senators to condemn their own members under Tiberius and he refused to listen to informers. He probably did not abolish the charge itself but removed the charge from those accused by Tiberius. Following his illness, Caligula very possibly used the charge of maiestas against Gemellus and others. He even made a show by burning the trial records relating to his mother and brothers to prove he bore no malice toward those involved in their prosecution. However, were these the original documents or just copies? Dio claims only copies were burned (59.4.3). The papers were probably Tiberius’ private documents rather than relating to senate trials since Agrippina and her sons were tried before the emperor in camera (Cal. 15.4). Augustus had similarly made a show of burning Antony’s incriminating letters after Actium but had no scruples about making use of them later. Once Caligula learned through his spies about the discontent brewing in the Senate and had read Tiberius’ private papers the maiestas charges he had dropped were reinstated. [7]

Caligula also recalled everyone condemned to exile during Tiberius’ reign. This was a bold move and Macro was probably behind Caligula’s decision in order to disarm any opposition (Cal. 15.4). Later, Claudius recalled exiles but went through the trial records carefully first before destroying them. The only named person that Caligula freed from prison was Publius Pomponius Secundus, who had sheltered Aelius Gallus (probably a nephew of Sejanus) following the fall of the Prefect. Secundus had been imprisoned and badly treated for seven years (Ann. 6.18; Dio 59.6.2). The former prisoner showed his gratitude in a way most pleasing to Caligula: inviting him to a lavish banquet where costly wines were served.

Caligula went further still and allowed the writings of long suppressed authors to be published. The authors, Titus Labienus, Cassius Severus and Eremietius Cordus were extraordinary choices. Labienus was an orator whose vicious attacks earned him the name Rabienus (rabid). Severus made slanderous comments about prominent men and women and was the first person charged with maiestas by Augustus. Cordus published a book outspokenly favorable to Brutus and Cassius during Augustus’ reign, and his writings were ordered burned. The new emperor claimed that such writings were of interest to all for posterity to have all events recorded. Copies of the works were sought out from private collections (Cal. 16.1).

Tiberius Gemellus, excluded from his inheritance, was a possible danger to the new regime - a rallying point for opposition. [8]  To defuse the situation, Caligula invested him with the toga virilis, adopted him as his son and granted him the title princeps iuventutis (Cal. 15.2; Dio 59.8.1). Philo thought this a ploy to place Gemellus under Caligula’s authority but the adoption may have been a condition of the senate when Tiberius’ grandson was stripped of his inheritance (Leg. 25.8). Even Caligula’s uncle Claudius received honors. On July 1, at the age of 46, he became his nephew’s colleague in the consulship. Long a member of the equestrian order, Claudius now became a senator and was allowed the additional distinction of presiding at the games for the emperor. For Caligula, too, the consulship was a distinction. The speech he delivered before the Senate on assuming office noted the abuses of the prior regime and promised that they would not be repeated. The Senate was so pleased by the speech that they ordered to be read annually - probably intended as a reminder to the emperor (Dio 59.6.7).

Caligula associated himself with Augustus, as part of his early reign propaganda, stressing his descent from the princeps and not Tiberius’ heir. The dedication of the Temple of Divus Augustus took place on August 30 and 31, coinciding with Caligula’s birthday and the last day of his consulship. The temple had been built during Tiberius’ reign but was left undedicated. Caligula appeared in triumphal dress accompanied by a choir of noble youths and girls. The event was marked by two days of games and a commemorative sesterius was issued showing Caligula sacrificing in front of the temple (Dio 59.7.1-4). A short time later, probably on September 21, Caligula assumed the title pater patriae and was awarded the corona civica. On the same occasion, the Senate voted him a golden shield. Each year on the anniversary of the meeting, the shield was carried to the Capitol by the college of priests, escorted by the Senate and a chorus of noble boys and girls, singing the emperor’s praises (Cal. 16.4).

Illness and the Aftermath

During the first six months of his reign, Caligula lived in a state of constant activity. The demands placed on him taxed his stamina and just as the summer ended, he fell ill (Leg. 14-21; Cal 14.2; Dio 59.8.1). Caligula’s illness was serious, probably life threatening, and news of it caused widespread consternation in every corner of the empire. Crowds slept in the open around the palace waiting for news. The equestrian Atanius Secundus said he would fight a gladiator if the emperor lived. As if not to be outdone, Publius Afranius Potitus vowed to give his life if the emperor was spared. Such extravagant offers were also made when Augustus was seriously ill (Dio 53.20.2-4; 59.8.3).

Scholars are divided on what caused Caligula’s illness: some have declared it a nervous breakdown, while others have suggested physical ailments. There is no way to know exactly what was wrong with Caligula since ancient sources provide no clinical information. There have been various modern theories about Caligula’s illness that include alcoholism [9], hyperthyroidism [10] and epilepsy. [11]  Epilepsy was mentioned by Suetonius as an illness Caligula had as a youth (50.2), but his description (inability to walk, stand, collect his thoughts and support his weight) is similar to fainting spells. However, the inability to collect his thoughts and transient seizures fit the profile of temporal lobe epilepsy (involving a single part of the brain rather than the whole). Such attacks leave the victim confused for a period following the attack. Temporal lobe epilepsy can also cause behavioral problems such as aggression, inability to maintain social relationships, preoccupation with religion and other psychotic problems. However it is uncertain if this diagnosis can be applied to Caligula. For the ancients to say Caligula was mad was an uncomplicated way to explain his often erratic behavior and allowed Claudius to distance himself from his nephew.

The exact timing of Caligula’s illness is not known. Dio says it occurred not long after his consulship ended. Philo says the illness was a nervous breakdown, attributed to his high living, and that it occurred in the 8^th month of his reign (mid October to mid November). News of the illness was brought by sailors as they returned home at the end of the sailing season (around mid November) (Leg. 15). September is the most probable month that would allow the news to travel to Egypt in November. A clue is provided by the Egyptian calendar. One of the months renamed in Caligula’s honor was called Soter (savior), and began on September 28. This could indicate that October was the month of Caligula’s recovery. [12]

News of Caligula’s recovery brought relief to the entire empire, and Philo notes it was celebrated with sacrifices by the Jews of Alexandria (Leg. 356). The emperor called in the pledges made for his life. Perhaps Secundus and Potitus were expecting a reward but ended by fulfilling their vows. Secundus fought in the arena, defeating two opponents and was dismissed (Cal. 27.2). The number of fights may fall into the standard procedure of gladiatorial combat, and so was not an indication of sadism on Caligula’s part. Dio says Secundus was killed (59.8.3).

Events immediately following the emperor’s illness took a dramatic turn. The universal good abruptly ended with three suicides: Gemellus, Silanus (Caligula’s father-in-law) and Macro. There is little information as to why these deaths occurred let alone when they happened, or that they were related. Suetonius groups the deaths of Gemellus and Silanus together while Philo lists all three together. Dio lists the deaths of Gemellus and Silanus at the end of 37 and Macro at the beginning of 38 (Cal. 23.3; Flacc. 16, Leg 23-65; Dio 59.8.1, 4.6, 10.6).

Gemellus was charged with anticipating Caligula’s death and waiting for a chance to benefit from his illness. Philo explicitly says there was a conspiracy. Suetonius says that Gemellus had a cough for which he took medicine that left an odor on his breath similar to an antidote for poison. [13]  Because he was a member of the imperial family, and thus treason to kill him, soldiers were sent to force Gemellus to take his own life. When handed a sword, Gemellus had no idea what to do with it and had to be helped to end his life. The affair was kept quiet and no report was made to the Senate (Leg. 30-31; Cal. 23.3; Dio 59.8.2). As a mark of contempt, Caligula had Gemellus’ gravestone make no reference to his adoption. [14]

Although during Caligula’s illness, the consuls would have been in charge of the Senate, there were ceremonies and routines (like the giving of the password to the guards) that were the responsibility of the emperor. These duties would fall to Gemellus as Caligula’s son and could be taken as ambition. Any support Gemellus received, particularly from Macro, might easily be construed as a conspiracy. It may be, as Philo says, that Gemellus was the object of a conspiracy. Certainly, the empire was impossible to share and people were liable to favor one ruler over another (Leg. 68).

A link between Gemellus and Silanus is not apparent. Dio’s account is confused, mixing the divorce of Junia (who actually died in 34) with her father’s death. He says nothing of an incident that may have caused Silanus’ downfall, simply reporting that Caligula resented his former father-in-law (Caligula had remarried by this time). Philo says that Silanus got into trouble for giving unwanted advice (59.8.5;Leg 63-65). Suetonius relates an anecdote that when Caligula sailed to Pontia and Pandateria to gather the ashes of his mother and brother, Silanus declined to accompany him because he tended to get seasick. Caligula suspected Silanus stayed behind in order to claim the empire for himself should his ship be lost (Cal. 23.3). Silanus was subjected to a public trial and Tacitus reports that Julius Graecinus was forced to commit suicide for failing to prosecute him (Agr. 41), which means that formal charges were lodged with the Senate. Before the trial could commence, Silanus killed himself with his own razor. Possibly, the story of Silanus plotting while Caligula was at sea became confused with his involvement in a conspiracy to replace him with Gemellus.

Suspicion of a conspiracy may have prompted Caligula to think seriously about the succession, and before the end of 37he remarried. The name of his new wife is uncertain; Suetonius gives it as Livia Orestella and Dio as Cornelia Orestina. She was from a distinguished family and engaged to Gaius Calpurnius Piso, related to the Piso accused of poisoning Germanicus. Suetonius says that Caligula took her at her own wedding banquet in the manner of Romulus and Augustus (Cal. 25.1; Dio 59.8.7). However, this serves to rescue Piso from a charge of collaboration with the emperor. [15] Piso was allowed membership in the Arval Brethren on May 28, 38, replacing Gemellus; an honor that may have been a reward for his compliance in allowing Caligula to marry his intended bride. The marriage was of short duration and the new empress was divorced probably after two months, according to Dio, not the few days of Suetonius. She was put aside because she did not become pregnant. Orestella was later banished along with Piso because she had taken up with him within two years of her marriage to Caligula. This must have occurred much later since Piso is attested as being in Rome until June 40. The marriage shows that Caligula was impatient to settle the question of his heir and did not act on personal whim.

Early in 38, Marco fell (Flacc. 13-16, Leg 32-59; Cal. 26.1; Dio 59.10.6). The precise time of his death is unknown. His future was woven so closely to Caligula’s that it did not seem possible that such a staunch supporter could be removed. The reason for his fall, according to Philo, was Macro’s desire to control Caligula. He gives no hint of a conspiracy but Philo’s purpose in writing was to produce a moral tract on the ingratitude of the emperor, not a history. Dio implies that several people met their deaths at Macro’s fall (59.10.7). Caligula’s illness was possibly life threatening, and Macro would have put himself in a position as potential regent should the emperor die. Even if only a temporary shift in allegiance, Macro would be suspect and have to be removed. After all, he had readily switched his allegiance from Tiberius to Caligula when it was in his interest.

Removing his old mentor required delicate handling. Macro’s appointment as Prefect of Egypt was certainly meant to put him off guard, like the granting of tribunician power to Sejanus. Now, the tables were turned on Macro. He was officially charged with adultery and pandering his wife; there is no mention of further charges. The sexual misconduct of the Prefect avoided revealing that a conspiracy had made Caligula’s position precarious. Dio says that Caligula compelled Macro and his wife Ennia to commit suicide. [16]   The suicide of husband and wife presumably protected the family fortune since the Prefect left enough money to have an amphitheater built in his hometown, Alba Fucens. [17]

Macro was a friend of Flaccus, who is mentioned as a supporter of Gemellus. He may have been in communication with Flaccus during Caligula’s illness in an effort to secure his loyalty should the emperor die. The despondency of the governor, when he learned of Macro’s death, thus becomes clear. Also, when Agrippa left for his new kingdom in 38, he traveled via Alexandria at Caligula’s request rather than the usual route through Greece. Could Agrippa have been asked to check on Flaccus? (Flacc. 26). In late October, 38, Flaccus was arrested by a detachment of soldiers sent by Caligula and led by a centurion named Bassus. Flaccus was seized while attending a banquet and conveyed to Rome where he was tried on unspecified charges. Significantly, Lampon and Isidorus, who had supported Flaccus, now took up the charges. Their inclusion in Flaccus’ prosecution lends support to the idea that there had been communications between Macro and Flaccus, and the same charges were now being applied to the Prefect. Flaccus was condemned but did not received the death sentence, perhaps because the evidence was not conclusive. He forfeited his property to the state but Lepidus interceded on his behalf to have Flaccus exiled to the Greek island of Andros, where he was later murdered by a detachment of soldiers (Flacc. 151, 156-9, 161, 173, 180f). Lepidus’ involvement has brought his motives into question.

1 - Z.Yavetsz, "Caligula, Imperial Madness and Modern Historiography" Klio 78(1996), 105.