The Romans and the Germanic tribes had very different ideas of what you did with defeated enemies. To the Romans you conquered them, pacified them, made friends out of any co-operative local leaders and elevated them in rank, killed any dissenters, colonised them and absorbed them.

To the Germanics you perahps took some of them as slaves, exacted some tribute from them, took hostages from them to secure peace and then more or less left them alone. Until the next war.

By the time Arminius returned to Germania from the Roman Army - in around 7 AD when Varus was taking up his new Governorship - it was pretty clear that the Romans were here not just to stay but to change things. Arminius' cousin had taken up a priestship in the Roman religion. He saw colonies being built in Germanic tribal territory, taxes were being levied and customs were being eroded.

While Arminius and his father had benefited from friendship with Rome, it was clear which way things were going. And with the arrival of Varus - who treated this wild, frontier province as though it were as passive and established as Syria had been - it was also clear that Roman rule was to get increasingly heavy handed.

Dio tells us:

(Varus) not only gave orders to the Germans as if they were actual slaves of the Romans, but also levied money from them as if they were subject nations. These were demands they would not tolerate. The leaders yearned for their former ascendancy, and the masses preferred their accustomed condition to foreign domination.

Arminius was also ambitious. In early western Germanic society there was rarely a single "chief" of a tribe - more like several noble families which were always jockying for dominance and influence in the tribal assembly. Arminius and his father had a powerful rival in Segestes - another Cheruscian chief who also had a good reason to hate Arminius. The younger man had run off with his teenaged daughter Thusnelda, who Segestes had wanted to marry to the chief of another tribe.

So Arminius began to see that defeating the Romans would not only free his people, but would also establish himself as the pre-eminent chief of his tribe.