How did Roman empire decline

The Roman Empire was plagued by several problems. One of them was no stable line of succession. When one emperor died, often the top generals would fight it out to see who would replace him, throwing the empire into a ruinous civil war. Once a new emperor was in place he would give a ‘donative’ (basically a huge cash bribe) to all the soldiers to keep them loyal to him, draining the treasury.

The Empire was split and remerged into the eastern and western halves several times from the 3rd century AD onwards. This was done to make it easier to defend the borders, and at first it worked well. But when the split became permanent in 395 it exposed a weakness – the east was richer, meaning it could raise more money from taxes and support armies and/or payoff rivals. The west had less money, so they struggled to maintain an army that could defend its lands.

Ultimately it was barbarian invasion that finished off Rome. At least the western half, since the eastern half lived on for another 1000 years as the Byzantine Empire. Waves of barbarian migration in central Asia pushed down into Europe, creating barbarian incursions of Rome’s northern borders, specifically the Goths and the Huns, and various Germanic tribes. Rome had several opportunities to peacefully grant land to them, which could’ve maintianed the peace and even strenghtened Rome, but they bungled it and turned them into enemies. They raided Roman cities, robbing them of wealth and wrecking the social order. Rome was forced to settle with them by giving them lands, in exchange for mercenary service to defend Rome from other enemies. However this caused two new problems: the mercenaries weren’t really loyal to Rome, they were loyal to their own chiefs. Second, as Rome gave away territory its tax base shrank, giving it more tax problems. This chain of events repeated several times, until the western Roman territory was whittled down to little more than Italy, a small strip of north Africa, and an isolated piece of northern Gaul. Soon the city of Rome was sacked, and it wasn’t long before Odoacer and his army overthrew the last emperor.

There were several other reasons too, such as a plague at the end of the second century, a series of terrible emperors in the third century, and debasement of the coinage as Rome’s gold and silver mines depleted.
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