The ancient empire ruled by **Augustus** during its height is the **Roman Empire**. Augustus, originally known as Octavian, became the first Roman emperor after the fall of the Republic, establishing the imperial system around 27 BC. His reign transformed Rome, ushering in the Pax Romana, a period of relative peace and stability across the empire that lasted for over two centuries. Augustus implemented significant political, social, and economic reforms, expanding the empire's territory and infrastructure, solidifying his power, and transforming Rome into a dominant cultural and military force in the ancient world.