Final answer:
Augustus Caesar became the ruler of Rome after Julius Caesar. He established the Roman Empire and ruled as the first emperor. Augustus centralized power and implemented reforms to strengthen the empire.
Step-by-step explanation:
The ruler of Rome after Julius Caesar was Augustus Caesar. He became the first emperor of Rome and established the Roman Empire, ruling from 27 BCE until his death in 14 CE. Following Julius Caesar's assassination, Augustus rose to power through political and military maneuvers.
Augustus Caesar decided to rule by establishing a new system known as the Roman Empire. He centralized power in his hands, making himself the sole ruler and gradually diminishing the powers of the Senate. He implemented various reforms, such as the creation of a new calendar and regularizing Roman currency, to strengthen the empire and ensure stability.