Which leader split the Roman Empire into two parts to make it easier to govern?

a. Diocletian

b. Julius Caesar

c. Caesar Augustus

d. Constantine

The correct answer is Constantine I.

Constantine split the empire into Western and Eastern parts and established a new capital in the East: Constantinople (named after himself, but the city was before called Byzantium).

Before him, Diocletian split the empire into 4 different parts, but Constantine united these parts.