Weakness of the Roman Army

It seems generally agreed that the main weakness in the Roman army was a general "lack of professionalism" (1). The army being structured as it was meant that important roles were based more on one's social standing than their skill at warfare. The army could not be maintained over long periods of time, as the soldiers within it were all landowners, and thus had a duty to maintain their lands that they had left behind. Armies that stayed abroad too long would end up with discontent soldiers, who could very well return to find their lands overgrown, overrun, or simply seized by the state or powerful landlords.

This social structure, combined with the need to constantly disband and reform armies of landowners, meant that Roman armies could be poorly trained and ill-suited to fight a more professional force. Some astonishing defeats, including the horrific battle of Cannae, showed how a smaller, better trained, more dedicated fighting force could decimate a less professional Roman army.

(The Battle of Cannae was a horrific defeat for the Romans, ending with the near annihilation of their entire fighting force).