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.
The Twelve Caesars
Octavian (not yet renamed Augustus) finished the civil wars started by his great-uncle, Julius Caesar. One by one, Augustus defeated the legions of the other generals who wanted to succeed Julius Caesar as the master of the Roman world. Suetonius includes descriptions of these civil wars, including the final one against Mark Antony that ended with the Battle of Actium. Antony had been Octavian's last surviving rival, but committed suicide after his defeat at Actium. It was after this victory in 31 BC that Octavian became master of the Roman world and imperator (emperor). His declaration of the end of the Civil Wars that had started under Julius Caesar marked the historic beginning of the Roman Empire, and the Pax Romana. Octavian at this point was given the title ("the venerable") by the Roman Senate.