The fundamental changes were not limited to the ways in which central rule was organized, for Caligula also dealt with a problem no emperor before him had addressed: the social rank of the emperor himself. Up to that point he had followed his predecessors’ example in allowing the Senate to confer extraordinary honors on him that, although they had raised the emperors far above the other members of the aristocracy, had at the same time remained permanently linked to the traditional aristocratic ranking. In its turn this system of rank was based on the various classes of senatorial office (consular, Praetorian, etc.) and thus ultimately on the structures of the old Republican magistracy, that is, on a political order that had not merely not foreseen the possibility of a monarchy, but had excluded it on principle. Thus at the heart of the matter was a paradoxical process: Precisely by undermining the traditional ranking system in order to place himself at the top of it, the emperor provided proof both of its continuing validity and of his having no independent claim to monarchical rank. When he allowed the Senate to award him distinctions, he confirmed that he needed the old Republican institution in order to manifest his social standing. By accepting honors he emphasized that he lacked them on his own.
Caligula is the only Roman emperor of whom it is reported that he grasped this very paradox and made an issue of it himself. Cassius Dio, writing about the first delegation from the Senate after the great conspiracy had been uncovered, reports that Caligula’s response was to prohibit the Senate from passing any furthers honors to him: “For he did not for a moment wish it to appear that anything that brought him honor was in the power of the senators, since that would imply that they were his superiors and could grant him favors as if he were their inferior. For this reason he frequently found fault with various honors conferred upon him, on the ground that they did not increase his splendor but rather destroyed his power” (Dio 59.23.3–4).
But what would a monarchical position of honor look like once it surpassed the limits of the old Republican order of ranking, which was the only such order existing in Rome, and had been in place for centuries? The coming weeks and months would reveal Caligula’s plans on the subject. His first priority was display of material splendor, since after the old political ranking this was the second way Romans showed off their social status. Caligula had begun to exceed conventional limits of luxury some time before, but in this respect, too, he altered his behavior after the sojourn in Gaul. The auction of the household goods of his predecessors can be interpreted not only as a source of income but also as a conscious break with elements that had previously served to represent the emperor’s social position. Thus fundamental changes in the way the emperor’s role was shaped were taking place here as well. Yet the decisive question remained: What, for the emperor, would replace traditional manifestations of rank? It was true not just of ancient Rome but of all pre-modern aristocratic societies that each individual’s social status became a reality only when it achieved visibility in public.
The circle of people closest to Caligula during his stay in Gaul was not entirely free of aristocrats; it was free only of Roman aristocrats. According to Cassius Dio, among the emperor’s entourage were the rulers of two client kingdoms in the Hellenic East whom he had placed on their thrones in 37, Julius Agrippa of Judaea and Antiochus IV of Commagene. Another such ruler, Ptolemy of Mauretania, seems to have gone to Lyon as well, but was then condemned to death by Caligula under circumstances that are unclear but may have had something to do with political changes in the province of Africa. These kings embodied another tradition, of sole rule established over the course of centuries in the Hellenic empires of the East. Such kings were independent of urban political structures and urban aristocrats; they headed political administrations that had grown out of their own household staffs and answered to the monarch alone. The rank of the aristocrats and nobles around such kings was linked to a court hierarchy at whose apex the king stood unchallenged. And, last but not least: Since the third century B.C. it had become customary in the East for the kings, who occupied a position so far above everyone else, to be worshiped as godlike beings, with cultic rites. In describing the turn of the year 39/40 during Caligula’s reign, Cassius Dio mentions particular concern in Rome when the news arrived “that King Agrippa and King Antiochus were with him, like two tyrant-trainers” (Dio 59.24.1). What looked liked tyranny from the perspective of Roman senators can be described in other words: Caligula was starting to alter the paradoxical and dangerous role he had played up to that point as an emperor in a republic, and to create an openly monarchical system.
Caligula’s swift return journey to Italy ended before the gates of Rome. He was at the shrine of the Arval Brethren outside the city walls near the end of May in 40, and possibly about the same time he received on the first occasion the embassy of Alexandrian Jews, led by Philo, in the gardens of his mother, Agrippina, which likewise lay outside Rome. Two circumstances above all probably kept Caligula from entering the capital immediately. Events over the previous few months must have made the situation in Rome extremely volatile; for that reason alone, concern for the emperor’s safety would have ruled out an official entry amid large crowds of people. Then again, a return from Germania without any ceremony at all would have looked like an admission of defeat. On the other hand, the emperor had expressly forbidden the Senate to provide any formal welcome and other honors, so that a triumphal procession of the usual kind was out of the question. In its place Caligula chose a new way to stage his return, one without precedent in Rome. It alluded to the events of the northern campaigns, surpassed all previous triumphs, and was so imposing that even Suetonius includes it among the few deeds of the “good” ruler Caligula. To achieve this, the emperor proceeded to his luxurious villas near Puteoli in Campania and prepared to demonstrate his power as he had been prevented from doing at the English Channeclass="underline" by triumphantly crossing the sea.
A bridge of ships a little more than three miles long was constructed in the Gulf of Baiae between Puteoli and Bauli (near Misenum). It consisted of a double row of cargo ships assembled from many places, with earth piled on top of them to make a road as solid as the Via Appia. At various intervals the road was widened to make space for resting places and shelters with running fresh water. When the entire structure was finished, Caligula put on the breastplate of the most famous ruler of the Greek world, Alexander the Great, which had been taken from his grave; over it he wore a purple cloak of the kind used by Greek military commanders, with gold decorations and jewels from India. Wearing a sword at his side, carrying a shield, and with a crown of oak leaves on his head, he sacrificed to the gods, first of all to Poseidon, the god of the sea, and Invidia, the goddess of envy, so that he himself would not be a target for envy. Then he rode onto the bridge from Bauli, accompanied by troops of cavalry and infantry. On reaching the other side he stormed into the town of Puteoli like a general bent on conquering it.