The Law of Primogeniture

In Europe from 500 AD to 1500, a thousand years. Lots of its contradictions were solved. But the system lasts for a thousand years until the accumulation of contradictions blows the system up. You can see it in the French Revolution if you want a dramatic example. In 1776, declares war on King George III, a feudal king in England. And it doesn't establish a king here. No more feudalism. We don't want it. We're done with it.