Octavian, later known as Augustus, was the first Roman emperor, ruling from 27 BC until his death in AD 14. Born in 63 BC, he was the adopted heir of Julius Caesar and played a crucial role in the transformation of the Roman Republic into the Roman Empire. His reign marked the beginning of the Pax Romana, a long period of relative peace and stability across the empire. Augustus implemented various reforms, including administrative changes and the establishment of a standing army. He also initiated extensive building projects in Rome, enhancing its infrastructure and public spaces. His leadership set the foundation for future emperors and significantly shaped Roman history.