An Emperor's Guide (How-To Guides for Fiendish Rulers)

I am a Roman emperor, and my empire stretches from the sunny Mediterranean to northern Europe. I can tell that you're impressed. There are several rules I follow to keep everything under control: It is my right to banish traitors to freezing Britain. I will conquer lands to gain riches―and more people to pay taxes and work for me. My buildings must be beautifully made with the best materials. And by the way, I'm pretty generous. I declare public holidays and allow my people to watch gladiator fights. You must agree, this is a brilliant plan to keep my empire strong. What could possibly go wrong?