The Romans, the huns, the mongols, the holy Roman Empire, the normans, the Muslims, Napoleon, The British, the Germans, the EU
All these had their chance and lost it, battered down by internal conflict or pressure from numerous jealous neighbours. But was it possible? Couldd any one of these have conquered Europe and made it one country? Can the EU still do so? What difference would it have made? How long would it have lasted? What do you think?