[breakem]

My two cents. The question isn't how did it fall, but how did it last so long. The fall of Rome was inevitable. A city could not continue to govern such a large area. The growth of population in the east, north and west made it impossible for Rome to control these areas.

For a couple of humdred years, the Romans would win a battle and then hire the vanquished army to serve as the Roman army in that territory. This practice along with splitting the empire into thirds, made it inevitable that Rome would fall and that the seat of power would be elsewhere.

[Cboldt]

A city could not continue to govern such a large area.

And maybe it shouldn't. Human nature and all that "rot." IMO, society is stronger when individuals take on responsibility, instead of vesting it in human "governors."