
Geoffrey U. answered 12/01/15
Tutor
New to Wyzant
History/Anthropology/Government/Strategic Policy
This is a good question. It will take some time to explain. I hope your test hasn't happened yet.
The best answer for the end of the Western Roman Empire is, arguably, a bunch of different times. I don't know what level of schooling you're in, but if you're in a collegiate level course, you'll probably define it a few different ways, and arrive at a few different answers. The best contending dates for the end of the Western Roman Empire are as follows:
115-118 AD Rome is at its zenith. It has the largest square mileage it has ever known.
~370s Rome starts losing huge amounts of land. This is attributed to unrest of local populations under Roman rule, and because the Roman legions are the single greatest expense to Roman Imperial government. When the distances required to continuing conquest became too far to maintain solvency, they experienced a huge drop off in monetary income. Thus the super expensive legions became too expensive to maintain, and the Romans began to outsource their armies. Groups such as the Huns begin to move west, displacing native populations, forcing them to infringe on Roman territory.
~405-406 Hordes of "Barbarians" cross the Rhine.
~410 Alaric and the Visigoths sack Rome.
~480 Flavius Julius Nepos Augustus is deposed by his magister militum, Orestes.
This is a pretty good resource on some extra reading that can be helpful.