The Aquila, one of the signa militaria. (A standard)
A question often pondered concerning the Roman Empire is what caused it to fall, and even more so, when and if it even fell, as it lives on through many cultural achievements over its glorious existence. Obviously, the process of deterioration took a long time; as the empire waxed and waned throughout its years, falling victim to either an internal or external threat, only to rise up against the odds and fight on to see another day, it slowly but surely began to lose the internal foundation that had kept it on its feet throughout the many centuries it lasted. But what exactly caused such a powerful and determined people to finally succumb to the changing world around them? Deadly plagues that wrecked throughout the populated (and even loosely populated) regions of the empire? Internal conflict that only tempted the outsiders, deemed “barbarians,” to come in and take something for themselves? Excessive payments by the emperors themselves to acquire material possessions found only in the corners of their world? No, a single problem can not be blamed for the fall of this civilization, but each problem must be stacked up to see how they, as a whole, achieved the ultimate demise of Roma.
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Like mentioned earlier, yes, there are many more causes for the ultimate downfall of the Roman Empire, but I cannot mention them all. (Unless I slowly incorporate the ideas into this post, something that would take too much time) Feel free to comment or even add more reasons for the destruction of Rome, for it adds to the purpose of this topic. I haven't done one of these in a long time, and I have even tried using some of the newer additions to the BBCode. (or however you'd accurately describe it )
Sources:
Wikipedia - Some pictures, backup
The Roman Empire From Severus to Constantine - Pat Southern
The Penguin Historical Atlas of Rome - Chris Scarre
The links for the pictures can be found by right clicking and choosing the 'Properties' option.