One group has control over another group that might have different linguistic practices, different culture. That's when it is considered an empire. Well, what's the general framework for how empires tend to form? Well, let's say that I am a ruler and I control this territory right over here. And either through my charisma, my military tactics, maybe I have a new weapon, some political intrigue, some weak neighbors, I'm able to conquer some more territory right over here. What does that do for me? As I expand, this gives me more land and more people to rule over.