As I mentioned, there has been a flurry of new books about the end of the Roman Empire.  It’s an interesting puzzle, with resonance for any empire:  how does something so solid and functional come apart?  Could anything have been done to prevent it?

But that is only one of the interesting questions raised by the Roman Empire.  The other, probably even more interesting, is how such an empire was created in the first place, and how, once created, it stayed together for so long.  This enterprise ruled the entire Mediterranean basin, and additional territories as far north as Britain, for many centuries. It built roads, administered justice, and kept down pirates and brigands.  It maintained cult temples, built arenas where prisoners and animals were slaughtered for entertainment, and fed urban populations from the produce of vast factory farms worked by slaves.  All at a level of technology no higher than anywhere else.

And how did they ever run it?  As Peter Heather observes, in The Fall of the Roman Empire (#2 in my Fall of Rome reading series), in a useful chapter called "The Limits of Empire":

Looking at the map with modern eyes, we perceive the Roman Empire as impressive enough:  looked at in fourth-century terms, it is staggering.  Furthermore, measuring it in the real currency of how long it took human beings to cover the distances involved, you could say it was five times larger than it appears on the map.  To put it another way, running the Roman Empire with the communications then available was akin to running, in the modern day, an entity somewhere between five and ten times the size of the European Union.

And keep in mind that the European Union has 27 member states.

Somehow, a mid-Italian city state had successfully emulsified all the old long-standing political and cultural entities of the Mediterranean basin and beyond.  And that emulsion didn't crack for nearly five hundred years.

Warlords with powerful regional bases tore the Late Republic apart, but it stayed together.  One emperor after another succeeded Nero, but it stayed together.  The ludicrous Commodus couldn't destroy it, neither could the deranged Caracalla or the bizarre Elagabalus.  The fifty years of constant civil war following the death of Alexander Severus, with dozens of emperors and usurpers, should have finally taken it down, but didn't.  Diocletian and Constantine's military/bureaucratic Dominate made the whole thing much less fun, but it stayed together.  By that point, it wasn't even ruled from Rome, but from regional strongpoints like Trier and Antioch.  And when the Western regions were finally torn from this system (including the original capital, Rome), the East kept together, like a smoke ring blown through history, for hundreds of years more.

The Fall is only noticable because it stood for so long without falling.  And the Rise was certainly not inevitable.  What would Western history have looked like if there never had been a Roman Empire in the first place?