The Roman Legions The Roman Legions were one of Rome's greatest armies ever. Many factors lead to the greatness of the Roman Legions. First, the Roman Legionaries were very well trained and disciplined. Next, they weren't as tough on the cities they conquered as many other forces were. Finally, the Legions setup well-designed fortresses or marching camps to help keep the enemy from easily attacking them. All of these state how the Legions were superior to other armies of its time and beyond. The Roman Legions were very well trained and disciplined. They spent a lot of their time practicing and improving their skills. Training was taught by at least