Specifically, here are my requirements,
1. Europe may never have any other empires after the Roman and Byzantine that hold territory outside of Europe. So, no British Empire, no Spanish Empire, no French Empire, and no Russian Empire. Now, this doesn't count empires based outside of Europe, which the Ottomans might count as, but that's it.
2. Following with this, no country i n Europe can ever project power out of Europe until the year 1900. Even then, it can't do so through direct territory acquisition, and can't be on the level of a superpower.
That's it. I'm curious because a world without Europe as the pinnacle of influence on it would be... interesting, to say the least.
Additionally, this is the most stubborn continent in human history, in this regard. The Black Plague, after all, didn't prevent Europe from holding the majority of superpowers, and pretty much all the hyper powers, in history. It took two World Wars to knock Western Europe from this role, and the Cold War to knock the Soviet Union from it.
Even with this, the world's current superpower owes much of that status to its European heritage, and isn't anywhere near as powerful as the British Empire at its height, relatively speaking.
Finally, to this day, the continent still holds the majority of the world's Great Powers, and still holds much of the world's most powerful economies(relatively speaking.)