Hadrian\'s Wall built to keep troops busy?

[Marcus Velius Avitus]

I have always heard that "keeping busy" served a dual purpose - occupied soldiers don't get into as much trouble (this is true NOW too!) and it developed lasting structures and infrastructure in the region (permanent impreovements). I would think that if you as an emperor or governor have a legion at your disposal, you would utilize them to BUILD something. It is absolutely true that idle soldiers get themselves into lots of trouble. I have seen it happen myself...

Indeed - Mithras said "Building was part of a legionary's job description" good way to put it!