Roman Emperor from 117 to 138. Britain was under Roman occupation during his reign, and he commissioned a stone wall across northern England, from Solway Firth to the Tyne, to protect southern Britain from the northern tribes.

In the Vulgate Merlin, Hadrian is introduced as the Emperor of Constantinople in Arthur’s time. His daughter married King Brandegorre of Estrangorre. Arthur’s Sir Sagremor was Hadrian’s grandson, and the intended heir to Hadrian’s throne. As Hadrian grew old and infirm, he faced a revolt from his Greek barons.