Watch Rome Power & Glory: Legions of Conquest

"Rome Power & Glory: Legions of Conquest" is a documentary about the evolution of the Roman Army. That army had begun as a citizens' army full of amateurs and gradually became a well-run professional military that conquered much of the known world. The documentary depicts some key battles, like Scipio's defeat of Hannibal. It also details how the military was weakened by its efforts to control an overly large empire and by fighting within the ranks.