What if Arminius Takes the Offensive?
It came up in my readings that Augustus briefly panicked, in the aftermath of the Teutoberg Forest disaster, thinking Arminius was going to next invade Gaul or Italy. This didn't happen and the Roman's retook the offensive against them a few years later under Germanicus. So what if instead Arminius lets say in spring of 10 AD leads his men in an invasion of the Roman heartland. What is the result? Implications? What forces would Rome have available to counter the threat?