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.
Fasti
Solinus observed that Gaius Pompeius Gallus and Quintus Verranius were consuls in Olympiad 207.1, and that this year was 801 AUC, counting from the foundation of Rome at Olympiad 7.1. By modern calculation this is 49 AD. He was relying on the official dating scheme, which must have been the "fasti consulares". In Varro's chronology this is AUC 802. Simple subtraction shows that AUC 1 in Augustus' fasti is 753/752 BC. The fasti give to the start of the republic a date of 244 AUC, but some editors "correct" all the AUC to Varronian. Similarly the fasti run to the death of Augustus in 13 AD (14 in the Varronian). This is not a difference in the starting date of the republic or the year of Augustus' death, which remain in the same years relative to surrounding events in either case; instead, the year of AUC 1 differs.