Tiberius was left with no male heir in the years directly before his death. He therefore took Germanicus' son Gaius into his palace and cultivated the youth. Upon Tiberius' death in 37, the Praetorian Prefect Macro, an acquaintance and ally of Gaius, proclaimed the latter as Princeps, and the Senate ratified the choice. Gaius was better known as Caligula, meaning 'little boots'. He had been taken by his father Germanicus on his several German campaigns, and had been equipped with miniature roman centurion's uniform, complete with little boots. Hence the nickname, which stuck. His rule begins the Julio-Claudian dynasty, all of whose members were descended by blood from Augustus (related himself to Julius Caesar), or to the latter's third wife Livia (previously married to T. Claudius Nero). Caligula began his rule well: he stopped the rash of treason trials, recalled political exiles, gave shows for the Roman populace, and brought his uncle Claudia, despised son of Antonia, into the political arena. In October of 37, though, Caligula became nearly fatally ill, and when he recovered, became a pathological monster.
In order for the Principate to function well, cooperation with the Senate was necessary. Caligula was not interested. He beat one consul over the head with a chair, and threatened to install as senator Incitatus—his horse. Offending the Rome aristocracy even more, he dressed as the gods in public, and even engaged in the games himself, as charioteer, gladiator, and singer. He proceeded to build a temple to his own divinity and engage in incest with his sister Drusilla. In 39, there was a conspiracy against him in the Rhine area legions. He killed the conspirators and then led the army into battle over the Rhine. Though the campaigns were marginally successful, those 'captured' Germans present at his triumph were in actuality Romans in disguise. Caligula then spent the winter in Gaul, readying his forces to cross over to Britain for a conquest. When they arrived to the channel in the summer, however, the legions were ordered simply to collect seashells.
This insanity was topped off by his most self-destructive craziness. Judaea had been a client kingdom since Pompei. Herod had been the last important king there. A Hellenized Jewish convert from Transjordan, Herod had been a friend of the Romans, and built great structures all over the kingdom. He had died in 4 BCE, dividing up the realm among his three sons, giving the core Judaean lands to his son Archilaus. Archilaus' rule was so poor and impious that the Jews petitioned Augustus to annex the area. In 6 CE Judaea was thus made a Roman province, ruled by an imperial procurature from Caesaria, a non-Jewish town. Back in Caesar's time, the Jews of Alexandria had supported him, so the dictator had accorded them certain privileges: they had religious freedom and could keep the Sabbath; they were not liable for military service; the taxes that went to the Temple in Jerusalem would not be diverted to the state fisc; and in Judaea itself, Roman coins would not contain the Emperor's likeness, out of respect to the Jewish ban on graven images. In the same vein, Jews were not required to participate in the imperial cult (deification). Here, Caligula erred. Alexandrian Greeks had resented the Jews' exemptions, and demanded that Caligula's statue be emplaced in the Jews' Temple in Jerusalem. Riots broke out in support of this in Alexandria, and Caligula, who was engaged in propagating his own divinity in any event, took over the notion, and commanded that his likeness—tantamount to an idol—be put in the Temple. Herod Agrippa, one of Herod's descendants, told him he was crazy, but Caligula commanded the Syrian governor to comply. The latter stalled, upon which Caligula threatened to kill him. In the event, the stature never arrived, because in 41 Caligula was assassinated by an officer of the Praetorian Guard whom the emperor had offended.
With no obvious successor, a political vacuum emerged. In chaotic circumstances, the Senate met to decide the fate of the Empire. There was talk of return to a dual consul republic, and some thought to choose the Princeps. In the meantime, Praetorian Guard members had discovered Claudius, Germanicus' younger brother, cowering behind a curtain in the palace. Taking him to the Praetorian camp, the Guard recognized him as emperor, with financial inducement. Though the Senate balked at first, Herod Agrippa interceded and negotiated senatorial recognition of the new Princeps.
Claudia was at first glance an unlikely choice, and was not viewed as suitable by the Roman elites. He was already fifty, had no administrative or military career, and suffered from physical defects such as weak legs and a lolling head. His mother had hated him and the rest of his family had not considered him Princeps material. Still, he was not without merits. Augustus had seen he was smart, and had spent late nights talking to him over drinks. Claudius was also an historian. He had written about Carthage, and he had also produced a forty- one-volume history of Augustus. Thus, he knew all about the Empire, its history, and how to administrate it. He was interested in governmental efficiency. Given this inclination and his deformities, it was no wonder that the Senate disliked him. Though he was not hostile to it as a body, he did revive the sensor to eliminate bad senators from the ranks, and abolished a number of senatorial offices duplicating imperial ones. He also installed larger numbers of equestrian procurators in senatorial provinces, reducing financial powers of senatorial quaestors. At times he interfered with proconsular appointments, and wrested control of the aerarium, the main Roman treasury. Thus, while all of this contributed to a greater administrative and policy efficiency, it incurred aristocratic ire as it dimmed the Senate's power.
Claudius proceeded to create a thoroughgoing Roman bureaucracy. While Augustus had been responsible for administrative changes, his rule had been exceedingly personal. The Princeps had himself to manage all matters, yet by the 40s and 50s, the amount of administrative matters was becoming too much for one person to handle. Claudius thus founded secretariats with Roman freedmen as their staff: 1) Narcissus handled imperial correspondence; 2) Palas oversaw finances; 3) Callistus handled petitions and judicial matters, while 4) Polybius' duties are unclear to us. Each of these was a quasi-minister with miniature ministries, and the secretaries themselves became rich and powerful, wielding influence over the Princeps himself. At the same time, the secretariats' existence aggravated Claudius-Senate relations. An additional role Claudius undertook regarded public works. A new harbor at Ostia was built, just as was constructed a Roman road from the Adriatic to the Danube. He also cared for the provinces, using the imperial procurators to monitor the (senatorial) quaestors.
On the domestic front, Claudius exhibited a liberal citizenship policy, expanding trends begun under Augustus. 1) He gave Latin citizenship to whole tribes in the Alps and Gaul. 2) He accorded Roman citizenship to growing numbers of native chiefs. Some chiefs in Gaul already had gained Roman citizenship, and now proposed to run for the office of quaestor, a senatorial- level position of usually financial investigative powers. This was legal given their newly acquired citizen status, but bound to incur senatorial ire. During an address to the Senate, however, Claudius indicated that the greatness of Rome lay in its acceptance of foreign elements. This forced the Senate to open the way to Gallic chief candidacy for quaestor and the senatorial position that would follow it, and Claudius used his control over the censors to assure their election.
In foreign policy, Claudius reverted to Augustus' policy of military expansion. He was served well by highly competent generals, such as Corbulo, Vespasianus, Plautinus, and Paulinus. He began with Mauretania in North Africa. Caligula had invited the native king to Rome, and when he arrived, ordered him to commit suicide. When the king did so, Mauretania revolted, and Claudius inherited the disturbance. In 41-42, Paulinus was sent there. Crossing the Sahara, he repressed the revolt, and Claudius annexed the region as an imperial province. Britain was next. It was a Celtic land, ruled by kings, one being Cunobelinus. He had a large kingdom in the west with his capital at Camuldunom. The region was not totally Barbarian, as it had a coin- based economy and trade relations with Gaul. Still, Claudius wanted it, and so sent Plautinus to ready the troops on the coast in 43. In 44, Roman troops crossed into Britain, defeating the two sons and heirs of Cunobelinus. Plautinus then waited at the Thames until Claudoius arrived, at which point Roman arms captured the capital. Claudius received a triumph, renamed the area Britannia, and named his son Britannicus. Plautinus then proceeded to reduce southern, central, and eastern England to submission.
Claudius' demise was unfortunate. His final two wives were the reason. He had Messelina killed after she publicly married her lover, who probably had plans to kill him in preparation for a joint usurpation. Pallas then suggested he marry Agrippina the Younger, daughter of Germanicus. He did this, and proceeded to adopt her ambitious son Nero. She then proceeded to kill several relatives that could prevent Nero's (and her) assent to power. Finally in 54 CE, Claudius sat down to a meal of mushrooms prepared by his new wife, and was dead the next day. Murder is quite likely. Upon this, the Praetorian Prefect named Nero as Princeps, and the Senate agreed.
Augustus was probably the most important figure in Rome's history from 30 BCE to 100 CE. In essence he solved the problem of how to govern Rome, and the Principate gave the Empire a lasting place in history. As well, the army was professionalized, and the solid beginnings of a professional civil service emerged by the 20s CE. Militarily, though the Teutoburgian Forest Massacre had been a disaster and Augustus forsook the notion of conquest to the Elbe, it is difficult to fault him for shortsightedness or strategic mistakes. There appeared in Roman terms nothing to be gained from conquest there. Also, the German lands were so politically and socially disorganized as well as backwards that they did not yet threaten Gaul. Police actions seemed to suffice in this regard, whereas full-scale conquest was quite difficult. Pushing back the frontier to the Danube, though, gave the urban civilization of the Mediterranean basin—the core of the Empire—a new security, while cultural changes began in the older tribal areas along the two rivers—the Balkans at least were to become Latinized, in some areas thoroughly. Finally, Augustus is attractive because he got better as he went along, and progressed from a bloody triumvir to a responsible governor, becoming the pater patria—father of the country.
Still, succession proved problematic, in that while Augustus could maintain in his person an ad hoc collection of supreme powers based on his Auctoritas, no one who followed him would possess his social power and esteem—he was peerless. In theory, though, Tiberius' accession could have been flawless. He was an able general and administrator, with years of experience of seeing Augustus make the Principate work. He was also not without reputation. From the start though, problems emerged. Perhaps he was less than gracious in his relations with the Senate, etc. due to his advanced age. Augustus lived so long that Tiberius waited in the wings for decades, at one time passed over as favored heir. Most importantly, though, there was simply no way to live up to Augustus' image. He developed a terrible reputation in Senate histories, mostly related to his use of murder. In comparison to later rulers though, he was undistinguished in this regard. Something that his Principate did begin to demonstrate, however, was the degree that the Senate and administration as a whole was in thrall to the Emperor. Still considering their state a republic, senators grew to resent the domination of the polity exercised by Tiberius in a way less subtle than his predecessor. As well, the vicissitudes of Tiberius' rule and reputation show that a problem with the new system was that Emperors stayed in power until they died, unlike traditional consuls, or even Sulla-style dictators.
Caligula manifests the latent difficulties of the Principate clearly. Indeed, as a whole, while the Julio-Claudians have been criticized by both contemporary as well as modern historians, they are pedagogically useful in that they make a simple point: the Principate was an advance to be sure, and Rome was politically stable with unchallenged external power. Still, a problem persisted in that the Princeps was too powerful and unchecked. Any change was therefore to be violent, and/or costly. There are no convincing reasons for Caligula's descent into depravity, cruelty, and lust. Perhaps it was because his life had been miserable until his ascent to power. His father may have been killed by Tiberius, and his older brothers were assassinated for political reasons, just as was his mother. In any event, he took Tiberius' cool attitude to the Senate to its logical conclusion, completely alienating them. And whereas the Principate possessed a collection of powers elevating the Emperor beyond the level of primus inter pares, at this stage, the state could not function effectively without good Emperor-Senate relations. Finally, Caligula's demise illustrates three key points. 1) Just as the Emperor now controlled the entire army in one person, without army support, the Princeps was nothing, and would fall precipitously; 2) A Roman-Greek cultural animosity continued. Just as Rome was coopting aspects of Greek Hellenistic civilization, a strident assertion of superiority over the erstwhile Mediterranean power made it perilous for a high roman official to be to devoted to a Hellenistic renaissance; 3) The Praetorian Guard had been established as a small, elite personal guard for the Princeps. However, Caligula's fall and Claudius' rise indicates that it, especially in the person of the Praetorian Prefect, could become a political player in its own right. As a sort of king maker, the Praetorian Guard would expand and abuse this role in the future, leading to it's disbanding in the late third century.
As regards Claudius, his negative representation in roman histories demonstrates two points: 1) The continuing penchant of Roman elites to privilege material and cosmetic concerns in social evaluation. To a great extent, Claudius' physical infirmities hobbled him from the start in his relations with senators; 2) Though pursuing the same policies of Augustus and developing continuations of his predecessor rather than innovations, his lesser glamour combined with his decreased care for the appearance of collegiality with the Senate mean that from Claudius, the term Imperator—Emperor—becomes truly appropriate to describe the status of Rome's ruler. Three further matters mark the Claudian era of rule: a) the Roman conquest of Britain, a relatively major territorial/political gain; b) his liberal granting of citizen rights and advocacy for Gaulic socio-political inclusion in Roman society, and c) his poor choice of marriage partners in Agrippina the Younger. In sum then, Claudius expanded the Empire and improved its administrative and fiscal effectiveness, just as he opened the door to its ethnic evolution. Also, he undermined the Senate, though not by intent, and he altered the nature of the Princeps.