Roman Emperor Hadrian ruled from 117 to 138 AD and is best known for consolidating and fortifying the Roman Empire's borders. He is famous for constructing Hadrian's Wall in Britain, which marked the northern limit of Roman territory and served as a defense against tribes from the north. Hadrian was also a patron of the arts and architecture, commissioning many buildings, including the Pantheon in Rome. His reign is often considered a period of relative peace and stability, known as the Pax Romana, which allowed for cultural and economic growth throughout the empire.