The main differences between the roman republic and the roman empire.

Rome was first a republic before getting converted into an empire. This might appear to be paradoxical to some as becoming a republic is a process that usually starts from autocracy. However, history tells us that Rome was a well developed republic with the rule of law and elected representatives in 100 BC but personal ambitions and power equations let to circumstances where it got changed into an empire.
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He droped it over the bridge into the river