The Fall of the Roman Empire One of the main cause of the decline of Rome was a weak Military. This is true because the Military was failing to not only win the battles against invasions, but also survive when fighting these battles. Rome was getting lazy, and did not want to wear the armor, (Roman soldiers in the past,) to protect them from enemies. This is a big deal because the Romans were getting slaughtered and beaten in battle with no armor to protect them from not only the enemies’ but also the assassins’ weapons. The weak Military was one of the main causes of the decline of the roman empire because of the soldiers’ laziness. Before 400 CE, the soldiers wore all of the armor the needed to win a battle, such as breastplates, and helmets,