Angrivarii
The wars began in the last years of the reign of Augustus, first emperor of Rome. Augustus died an old but respected man in the year 14 and was celebrated with much pomp and splendor. He left a document to be read to the senate posthumously, expressly forbidding extension of the empire beyond the Rhine. News of the will was welcomed by the Germans, thinking it gave them a free hand in the region. Germanicus found it necessary to pacify the border, which he did by a combination of scorched earth raids and offers of alliance with Rome - in short, stick and carrot. These raids also kept the army of the lower Rhine distracted from the possibility of mutiny, which had broken out on Augustus's death and only been quelled by concessions and executions.
Julius Caesar
Because Caesar's clemency had resulted in his murder, the Second Triumvirate reinstated the practice of proscription, abandoned since Sulla. It engaged in the legally sanctioned killing of a large number of its opponents to secure funding for its 45 legions in the second civil war against Brutus and Cassius. Antony and Octavian defeated them at Philippi.
Afterward, Mark Antony formed an alliance with Caesar's lover, Cleopatra, intending to use the fabulously wealthy Egypt as a base to dominate Rome. A third civil war broke out between Octavian on one hand and Antony and Cleopatra on the other. This final civil war, culminating in the latter's defeat at Actium in 31 BC and suicide in Egypt in 30 BC, resulted in the permanent ascendancy of Octavian, who became the first Roman emperor, under the name Caesar Augustus, a name conveying religious, rather than political, authority.