"The Roman empire?" Tomcat had its head buried in the cabinet as it tidied it up. "The Roman empire is a classic case of a centrally controlled ancient empire. Even though its form of government wasn't as stable as ancient China of the same era, it was one of the few massive nations in history that ruled all of Europe. At its peak, the Roman Empire territories were big enough to make the Mediterranean Sea a continental sea. After ancient Rome fell, until the Earth's disappearance, Europe has never come under unified rule again."
"The Roman Empire fell in the fifth century."