The Roman Empire (60 BCE-160 CE)
By 47 BCE Caesar had won the civil war against Pompei, and soon became dictator, planning a major reconstruction of republican government. He was assassinated in 44, however, by a conspiracy of senators acting to save the Republic. Marcus Antonius then stepped forward as major claimant to power, while the Senate coalesced around Octavian, an heir listed in Caesar's will. After indecisive battles, the two put off final conflict in a second triumvirate, including Lepidus. Finally, the former two broke, and in 30 BCE, Octavian defeated Mark Antony at Actium. In the next twenty years, Octavian (now named Augustus) created the Principate, a new form of Roman government giving increased powers to a non-elective Princeps who would evolve into Emperor by the mid-first century CE.
Tiberius took over as Princeps in 14 CE, having established a solid military reputation in the Rhine area. His rule was characterized by increasingly withdrawn and autocratic power. His successor, Caligula, went quickly insane, prompting the Praetorian Guard to murder him and proclaim Claudius Emperor in 41 CE. Less glamorous than his predecessors, Claudius did contribute to increased regularization of imperial administration, and enfranchised new elements into the roman elite, such as equestrians and some Gaulic chieftains. He in turn was succeeded by Nero in 55, who, after five good years, rapidly declined into a murderous depravity. After executing some of the Empire's best generals and senators, he committed suicide in 69, while four generals were in open revolt, and Judaea was in arms against imperial control. Germanic tribes were also acting up.
After Nero, four claimants to power emerged. Vespasianus (r. 69-79), the commander in Judaea, emerged as victor from this Year of the Four Emperors. He established the Flavian dynasty, represented by his sons Titus (80-81) and Domitian (r. 81-96). A more sober administration emerged, bringing more equestrians into service, with the Emperors themselves not originating in Rome. Conflicts with Germanic tribes such as the Quadi and Marcomanni indicated the future difficulties, while Dacian marauding in the Danube region provided opportunities for Roman conquest, realized under Nerva (96-98) and Trajan (98-117).
The most popular Roman Emperor after Augustus, Trajan also engaged in eastern conquests against Parthia, yet died before the troubled regions could be adequately secured. His successor, Hadrian (117-138), abandoned Parthian expansion, yet maintained gains in Dacia and Moesia, allowing the gradual process of Romanization and Latinization to begin. In his attempts to administratively regularize all regions in the Empire and rationalize Italy's judicial districts, he incurred the resentment of Italian elites, and died unpopular, for this as well as for his lack of conquest. The reign of Antoninus Pius (138-161) showed Rome entirely at peace and with great wealth, though the economy remained under-developed and extractive. All the while, German tribes had been migrating west and congesting the Danubian and Rhine border areas.
From the 160s, the Emperor Marcus Aurelias was forced to deal with Marcomanni, Sarmatian, and Quadi incursions across the Rhine and Danube in numbers never seen before. Though ultimately able to beat them back, the campaigns increased in cost, made field generals more popular and restive, and were a sign of looming problems.