Hadrianus, also known as Emperor Hadrian, was a Roman emperor who ruled from 117 to 138 AD. He is best known for consolidating and fortifying the Roman Empire's borders, particularly through the construction of Hadrian's Wall in Britain, which marked the northern limit of Roman territory. Hadrianus was also a patron of the arts and architecture, commissioning many buildings, including the famous 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.