Don’t expect the definitive answer to that one! I can only tell you today about the causes Edward Gibbon assigns to history’s favorite catastrophe. In fact, I can really only report on the causes Gibbon has mentioned in the pages I’ve read. His monumental classic, The Decline and Fall of the Roman Empire, encompasses 4,000 to 5,000 pages in unabridged print editions, pages containing altogether over a million and a half words. Since, according to manybooks.net, War and Peace comes to only 562,579 words, Gibbon’s history is nearly three times as long as what’s proverbially considered fiction’s lengthiest achievement. I’ve read about 7% of those 5,000 pages by now – a mere 100,000 words. So, no, I don’t have the definitive answer. But I have the beginnings of one.
Along the way of recounting the saga of crowns and conflicts, Gibbon takes the opportunity to deliver several lessons on life, a charming habit sadly left unindulged by many modern historians (and most music historians). Just yesterday, for instance, in a section devoted to the third-century emperor Decius’ sincere attempt to reestablish the office of censor, I read this: “A censor may maintain, he can never restore, the morals of a state.” (I love the Latin convention of linking sentences by a shared grammatical object and then leaving that object unstated in the first clause. And I love seeing the idiom find its way into Gibbon’s style.) In other words, national rectitude must be popular; it can’t simply be decreed.
Some of Gibbon’s lessons come from his reflection on the different levels of culture and education that he finds in the various societies taking part in his story. “The use of letters,” he concludes, “is the principle circumstance that distinguishes a civilized people from a herd of savages incapable of knowledge or reflection.” It might be guessed that Gibbon would not have included “plz” or “lmao” in his conception of a civilizing use of letters. Again with the Goths in mind, Gibbon observes that money “is the most universal incitement, iron the most powerful instrument, of human industry.” In other words, civilization depends partly on the metals the ground offers to its inhabitants. I once read a high-school American history text written around 1900 that began by acknowledging the propitious abundance and variety of natural resources afforded by the North American continent. By comparison, the high-school history text I actually read in high school started with explorers; in other words, its (hidden) lesson was that people can take all the credit for their successes.
As for The Lesson that his title promises, Gibbon actually cites an exact moment at which the decline began. After the death of Septimius Severus in 211, his son Caracalla paid the Praetorian Guard an exorbitant sum to secure his accession to the imperial throne. After this, Gibbon explains, the Guard and the legions who sometimes competed with them in the game of emperor-making, came to expect only riches from their Commander-in-Chief rather than discipline. And once a nation’s fighting force obtains a sense of entitlement, it gains political power, making the Senate weak, and loses military power, making the neighbors hungry.