@kara I reeeeeally wasn't thinking that far ahead! Lots of water passed between then and now. I shall ponder.

But there's often a rise-and-fall pattern of empire that is much more apparent in Asian and Middle Eastern empires than European, where it lasts 3-5 generations before falling apart. Moguls and other Gunpowder Empires, certain caliphates, others recognized by Ibn Khaldun even in the 14th century. The Big Important Empires are the ones who avoided the typical generational sine-wave.