Born the son of slaves, Diocletian was a native of Dalmatia – and possibly grew up in Salona, next door to Split. Despite his humble origins he proved himself quickly in the Roman military, becoming emperor in 284 at the age of 39. For 21 years he attempted to provide stability and direction to an empire under pressure – goals he achieved with some measure of success. Believing that the job of running the empire was too big for one man, however, Diocletian divided the role into four, the Tetrarchy, carefully parcelling out responsibility among his partners – a decision which some historians believe led directly to disintegration and civil war. Diocletian was also renowned for his persecution of Christians: those martyred during his reign included the patron saints of Split, Domnius and Anastasius, along with many other leading religious figures – Sebastian, George, Theodore and Vitus among them.
The motives for Diocletian’s early retirement have been the subject of much speculation. It was obviously planned well in advance by a man who feared he was no longer up to the rigours of government. As a highly innovative emperor, Diocletian obviously saw the very concept of retirement – a total novelty among Roman rulers – as a logical adjunct to his other reforms. However, the power-sharing system he left behind soon disintegrated once he was no longer at the helm, leading ultimately to the rise of a new strongman, Constantine the Great (ruled 309–38).