If Tacitus is to be believed, Agrippina was in fact scheming to hasten her sons’—and hence her own — rise to power. If so, she would have represented a real threat to the emperor. The problem cannot be reduced to the individuals involved, however, since it was structural in nature. A very high degree of skill was required — not just of the emperor in his political role, but also of the members of his family — to master the extremely complex relationships among them, which clearly involved mistrust and intrigue. In the end it is hardly surprising that most of them would prove unequal to the task. Caligula himself represented an exception in this respect, as time would show.
The next victim was his eldest brother, Nero, who had become the leading candidate for the throne after the death of Drusus (II). A marriage had been arranged for Nero with his cousin Julia, who was Drusus’s daughter and thus a granddaughter of Tiberius. The household he thus acquired seems to have been instrumental in his downfall. “In spite of the modesty of his youth”—thus Tacitus characterizes the syndrome of inadequacy described above — Nero “too often forgot what the times demanded” (Tac. Ann. 4.59.3). Tacitus reports further that Nero’s freedmen and clients were hoping to gain influence themselves if he became emperor, so they urged him to show vigor and confidence. The people and the army were behind him, they said, and Sejanus, who was now exploiting the trust of the aging emperor, would not dare to make a move against him. The Praetorian prefect had covert informants placed in Nero’s house, however, and they carried any incautious remark elicited from Nero straight to Sejanus and the emperor. Nero was not even safe at night, for whether he was awake, or slept, or sighed, his wife, Julia, supposedly told her mother, Livilla, about it, and she passed the information on to her lover Sejanus. For his part Sejanus now fed the feelings of rivalry and envy in Nero’s brother Drusus (III), whom he won over and encouraged in his hopes for the throne. The time was ripe in the year 27, when Nero was twenty-one and Tiberius already settled on Capri: Agrippina and her eldest son were placed under arrest. Soldiers were assigned to guard them; to watch over all their activities and contacts, including the letters and visitors they received; and to report everything they said.
These events, to which the fourteen-year-old Caligula was an immediate witness, meant that a new home had to be found for him and his two young sisters, Drusilla and Livilla. (Their sister Agrippina married shortly thereafter.) The three children moved into the house of their great-grandmother, Livia, the widow of Augustus who as grande dame kept up associations with many aristocrats and had a corresponding degree of influence.
She is supposed to have intervened to prevent Agrippina and Nero from being placed on trial and condemned. She died two years later, at the age of eighty-six, and Caligula appeared in public on that occasion and delivered her funeral oration. Once again it was necessary for Germanicus’s children to seek a new home. In the year 29 Caligula and his sisters moved to the house of their grandmother Antonia Minor, the other grande dame in Rome during that era. Antonia was well connected not only in Rome, but also in the East. Through her father, Marcus Antonius, and his relationship with Cleopatra, she had ties to several rulers there, who functioned as “client kings” of Rome, and their families. Several princes were also living in Antonia’s house at the time and got to know Caligula; later on the relationship would stand them in good stead.
Caligula’s stay in Antonia’s house was destined to last only two years. During this period — as Sejanus’s power was approaching its peak — the final downfall of his mother and eldest brother occurred. The emperor himself had written a letter accusing them of various crimes. Because of a gap in Tacitus’s Annals and the abbreviated accounts of Suetonius and Cassius Dio, their trial before the Senate cannot be reconstructed in detail. But if we do not know which senators aided Sejanus in instigating it, we do know its outcome: Nero was declared hostis, an enemy of the Roman polity, and banished to the island of Pontia; Agrippina was exiled to the island of Pandateria. The circumstances of Nero’s death on Pontia — probably in the year 30—remain unclear; he may have been starved to death or have killed himself, possibly driven to suicide because he believed he was about to be executed: Suetonius reports that an executioner was sent to Nero to show him the noose and hooks.
In that same year Caligula’s brother Drusus (III), who stood next in succession to the throne, came under attack from Sejanus and his minions. Like Nero he was accused of conspiring against the emperor. For years agents had shadowed and eavesdropped on him as well, activities in which his wife, Aemilia Lepida, is said to have played an important role. Caligula, at that time seventeen or eighteen years old, witnessed how Drusus was thrown into a dungeon on the Palatine Hill, from which he would never emerge. Not much later he too was declared a hostis; in his trial the senator Lucius Cassius Longinus served as prosecutor, a role that earned him Sejanus’s goodwill.
There is little reason to doubt what the sources say about how the members of Germanicus’s family were eliminated. In part the authors based their accounts on sessions of the Senate, for which minutes were available to them. The violent deaths of Caligula’s mother and brothers are thus firmly established. It is unclear, however, what was going through Tiberius’s mind in those years. Suetonius asserts in hindsight that Tiberius had planned to kill the members of Germanicus’s family from the start and simply used Sejanus to carry out his will. This claim attempts to explain the brutality of their deaths, but it is not very plausible. According to Cassius Dio, people had concluded Tiberius was mad, because he ultimately brought up the details of their deaths before the Senate, giving himself away completely. It must be assumed that the emperor had lost a sense of reality as he suffered constant fear for his own safety; the fear was actually heightened by his withdrawal from Rome and the influence, on Capri, exerted by his immediate environment, which Sejanus was controlling. In Rome fear must have been the dominant emotion in the Senate as well, for otherwise it is impossible to explain the senators’ reaction to the detailed reports about how Agrippina, Nero, and Drusus were spied upon: Although in fact they were appalled at the emperor’s behavior, as Tacitus reports, they pretended that what horrified them was the supposed enmity within the imperial family.
It took no great skill for Romans to figure out who was next in line, and accounts exist of several attempts to eliminate Caligula, too. Later, after the fall of Sejanus, several senators were prosecuted for attempting crimes of this kind. Sextius Paconianus was alleged to have helped the Praetorian prefect to organize an intrigue against Caligula. Cotta Messalinus and a close confidant of Tiberius named Sextus Vistilius were accused of having spread rumors about his dissolute morals. (Allegations of sexual misconduct had also played a role in the case against Nero.) Everything suggested then that Caligula would soon be placed on trial as well, but things took an unexpected turn.