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.
Caligula
Caligula (; Latin: "Gaius Julius Caesar Augustus Germanicus"; 31 August 12 – 24 January 41 AD) was Roman emperor from AD 37 to AD 41. The son of the popular Roman general Germanicus and Augustus' granddaughter Agrippina the Elder, Caligula was born into the first ruling family of the Roman Empire, conventionally known as the Julio-Claudian dynasty. Germanicus' uncle and adoptive father, Tiberius, succeeded Augustus as emperor of Rome in AD 14.