In Roman terms, an emperor is:

• A. A provincial governor appointed by the Senate.
• B. The high priest of Roman state religion.
• C. The sovereign ruler of the Roman Empire, holding supreme authority over the state and military.
• D. A magistrate elected to lead the Roman Republic.

Answer: (C)

The key idea is who held supreme power in Rome after the shift from Republic to Empire: the emperor as the sovereign ruler. In the empire, one man centralized authority over both the state and the army, commanding imperium across all provinces and directing military and civil policy. This role is what defines an emperor, distinguishing it from earlier Republican offices like provincial governors or magistrates, who operated within a system of shared power and elections. While later emperors often also held the religious title of Pontifex Maximus, that priestly role is secondary to the core function of ruling with ultimate authority over state and military. So the best description is that the emperor is the sovereign ruler of the Roman Empire, with supreme authority over the state and the military.