The third century AD was one of unprecedented crisis and chaos for the Roman Empire. Nightmares both internal and external threatened to spell the end of Rome’s thousand-year history. Diocletian was born either a slave or a freedman, and he grew up to become the saviour of Rome in her hour of crisis, a powerful military and political leader who transformed the Roman Empire from a hotbed of unceasing strife and turmoil into a renewed, restored, revivified and stable polity. His more than twenty years of power were marked by the ill-fated Great Persecution of the Christians, an undertaking that would prove to be one of the less successful initiatives of his reign, even as in its own way it helped to pave the way for the coming of an equally famous, successful emperor in the person of Constantine the Great. The present study seeks to provide an introduction to the life and times of Diocletian for the general reader, offering a balanced portrait of an immensely talented man in a time of trial and tumult, an accomplished emperor who knew when it was time to retire to his gardens.