Emperor Antoninus Pius ruled from 138 to 161 AD and is known as one of the "Five Good Emperors" of the Roman Empire. His reign was marked by peace and stability, with little military conflict, allowing for economic prosperity and cultural development. Antoninus Pius focused on legal reforms and the welfare of his people. He built public works, such as temples and roads, and promoted the arts. His leadership style emphasized diplomacy over warfare, contributing to a relatively harmonious period in Roman history.