Ok, somehow this topic started cropping up over in the White Santa thread confused and so rather than totally derail that, I thought I'd open a history-buff thread on it here. What caused the fall of the Roman Empire? I teach on this fairly often, and as a medievalist, the empire's breakup is the starting point for my own special interests, so I have firm opinions on it. Anyone with thoughts, questions, arguments, rotten fruit to throw, etc., is welcome to join in. The view one most often hears is what I call the "neo-Gibbonite" view, because it's based on the work of Edward Gibbon's massive masterwork, The Decline and Fall of the Roman Empire, published back at the end of the 18th century. Gibbon's view ran something like this: The empire finally collapsed in the 5th century because of a combination of internal decay (the "decline" part) and external pressure (the "fall" part). For internal decay, he believed moral corruption was largely to blame, along with Christianity teaching people to focus on otherworldly theology rather than this-worldly matters like law and military strategy. For external pressure, barbarians attacking the frontier and pushing into the empire proved to be too powerful for this increasingly weak empire to resist, finally leading it to be carved up among various barbarian chiefs. Gibbon was a genius and Decline and Fall is a true masterwork. He is to history what Isaac Newton is to physics. His work has set the paradigm for centuries since and continues to set the terms of discussion today. But just as Newton's physics have been superceded by relativity and quantum mechanics, Gibbon's interpretation is over 200 years old and new models cast it into serious doubt. Neo-Gibbonites usually (not always) discard the rise of Christianity as a factor, rightly. The eastern half of the empire was indisputably more thoroughly Christianized than the west, yet it was the west that broke up while the east survived the fifth century and carried on (we call it the "Byzantine Empire" once it no longer controls Rome, but it was still the continuing Roman Empire). As for general claims of immorality, luxurious living, corruption, etc., there is no real evidence that there was more of this in the late empire than there had been in the earlier empire. Roman moralists ALWAYS complained that people were less dutiful and virtuous than their ancestors, not because there was any real decline in morality but because that's the way moralists talk in every era. It's often claimed that the late empire's army was far weaker than the early empire's legions had been. This is also highly doubtful. If you look at the actual record of battles won and battles lost, the late empire's military had about the same batting average as the early empire's. It was unquestionably a larger and more expensive army than the early empire had. Its equipment was about the same. Military manuals from the early Byzantine period (there are several from the 6th-9th centuries) show a military establishment that was very adaptable and willing to adjust its tactics to meet new challenges, which doesn't seem like a sign of weakness. As for those barbarians - you run into a problem with the numbers. By most estimates, the empire had a population in the ballpark of 100 million. Now, one often hears language of "mounting pressure" and "barbarian tides" breaking down the empire's frontiers, but where did all this "pressure" come from? Reliable numbers are hard to come by in the ancient world, but the very largest groups seem to have had maybe 10,000-20,000 male warriors, plus women, children, and slaves - maybe 60-100,000 people on the move total. That would have been the handful of largest groups - Visigoths, Vandals, one or two others. One can come up with a couple dozen other groups on the move in the late empire but they were MUCH smaller, half that size at most. So how would an empire of 100 million be "overwhelmed" by pressure from maybe 500,000 barbarians (and not all at once), especially remembering those barbarians were poorer, lacked literacy, etc? These barbarian groups certainly were a factor in the world that arose out of the wreckage of the empire, but they don't work very well as an explanation for what broke it up in the first place. All in all, I'd argue that neither Gibbon's nor the neo-Gibbonites' take on how the empire broke up is really persuasive from our actual evidence. This is getting long so I'll post my view of what DID happen in a second post.