Legend tells us that Rome was founded by (and named after) Romulus, who later murdered his brother Remus for criticizing the city. Eight hundred years later, around 100 A.D., the Roman Empire was at its peak. It included half of Europe, most of the Middle East, and the northern coast of Africa. How did Rome grow so large? What caused its downfall? These are just two of the questions asked by historians and students ever since.