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.
History of Rome
However, the growth of the Imperium Romanum (Roman power) created new problems, and new demands, that the old political system of the Republic, with its annually elected magistrates and its sharing of power, could not solve. The dictatorship of Sulla, the extraordinary commands of Pompey Magnus, and the first triumvirate made that clear. In January 49 BC, Julius Caesar the conqueror of Gaul, marched his legions against Rome. In the following years, he vanquished his opponents, and ruled Rome for four years. After his assassination in 44 BC, the Senate tried to reestablish the Republic, but its champions, Marcus Junius Brutus (descendant of the founder of the republic) and Gaius Cassius Longinus were defeated by Caesar's lieutenant Marcus Antonius and Caesar's nephew, Octavian.