The Romans were able to spread their empire and control throughout Europe, Northern Africa, and the Middle East. While it is hard to know the exact numbers, at it's height the Roman empire likely comprised of between 50-75million people. The powerful Roman armed forces violently conquered and looted other groups and civilizations for 100's of years. Once conquered, the Romans attempted to assimilate local populations into their empire. One strategy they used is known as "Divide and Rule". Essentially, the Romans would offer benefits to groups they conquered, if they would help the Romans control neighboring groups in the empire. If a conquered group helped supply people to the Roman army, gave them information about a neighboring kingdom that was planning to revolt, or helped the Romans make more money through trade, the Roman government would offer the leaders of the group Roman citizenship, protection, money, food, and/or tax exemptions. In this way, areas of the empire that were far from Rome were incentivized to keep a close eye on neighboring regions and cooperate with Roman objectives. Roman approaches towards acquisition and administration of conquered territory and individuals provided the foundation, the blueprint, for later European expansion and rule. This system of dividing up the enemy into component units, making unequal alliances, and offering unequal perks was used quite effectively by all modern European imperialists: The British and French used the divide-and-rule system in North America, in India, in Africa, and the in East Asia; the Dutch in Africa and Southeast Asia; and the Spanish in South and Central America. Through this process, Rome became the economic, political, and social center of the western world.