2. The Roman army was one of the most powerful and disciplined in the world. Rome's success on the battlefield allowed it to conquer and control a vast territory, which stretched from Britain to North Africa and from Spain to the Middle East. Rome's political stability was also essential to its growth. The republic was governed by a system of checks and balances, which prevented any one person or group from becoming too powerful. This system allowed Rome to avoid the internal conflicts that plagued many other ancient civilizations.