What form of government was practiced in the Roman Empire

The Romans had three forms of government. The first was the monarchy. The second was the republic. The third was the principate. In the monarchy, the king was the supreme authority and his whims or words were laws. In the republic the people were allowed to elect officials who would speak for them. In the principate, the powers of the magistrates of the republic, in particular those of a dictator, were invested in one man who we call an emperor.