- "It was luxuries like air conditioning that brought down the Roman Empire. With air conditioning their windows were shut; they couldn't hear the barbarians coming."
– Garrison Keillor
- "Look back over the past, with its changing empires that rose and fell, and you can foresee the future, too."
– Marcus Aurelius
History has proven that a strong state wishes to subjugate other states - whether by force of arms or by economic force. Mighty rulers are greedy by definition, otherwise they wouldn't be neither mighty, nor rulers. Thus, defining the borders of an empire, and defending these borders becomes as important as expanding them.
After developing this Civic, a civilization's borders become 'inviolate', that is, if anyone enters them without permission, it constitutes an act of war. At the same time, you are granted the opportunity to 'allow' other states into your borders, whether as a part of a diplomatic trade, or as an act of kindness (understand 'bribe' - there is no kindness in diplomacy!).
Civilopedia entry
The natural pattern of nations is that one state, for whatever reason, becomes more powerful than its neighbors economically and/or militarily and conquers them … creating an “empire.” The more it conquers, the stronger it gets, and so it conquers more and more of its neighbors. Eventually inertia sets in and the empire stops expanding – sometimes because it meets neighbors stronger than it is but more often simply because it has become inefficient and venal, and it is inconvenient to fight wars of conquest so far from the center. Often the expanse of the early empire is determined by the state of technology, in terms of communications and transport. At some point, the empire weakens and breaks apart into smaller states … and the cycle begins anew.
The first “empire” was the Akkadian, established by Sargon in Mesopotamia c. 24th Century BC, an achievement matched later by Hammurabi of Babylon in the 17th Century BC. In the 15th Century BC the New Kingdom of Egypt, ruled by Thutmose III, was the standard for empire. Around 1500 BC arose the Shang Empire in distant China, to be followed by the Chou Empire 400 years later – its collapse was followed 550 years later by the Qin c. 221 BC. The first empire in civilization comparable to imperial Rome was the Neo-Assyrian; there followed the Median, Babylonian again, Persian, Macedonian (briefly) and so forth.
But it was Rome that set the standard. Thanks to their skill at organization, engineering infrastructure, military innovation, cultural flexibility, and economic clout, the Romans established the most influential and stable empire the world has seen. Indeed, the Latin word imperium has been used ever since to refer to empires such as the Umayyad, Ottoman, Spanish, British and even the American. And each in turn took up the claim of the Roman Cicero, who wrote that an empire exists because it has a “civilizing mission” to bring prosperity and peace to the world – whether the world wants it or not.