The Palaces of Diocletian and Ivan Mestrovich in Split, Croatia

In addition to persecuting Christians (notably the captain of his praetorian guard, St. Sebastian) and being the grandfather of Constantine the Great, the emperor who converted to Christianity, Diocletian (236-316) is notable for being the emperor who reformed the imperial system, deciding the Roman Empire was too large to be administered from one center and therefore splitting it, attempting to provide for orderly succession, ending the pretense of republican rule, and being the first emperor to retire.

Diocletian was born of a commoner family somewhere in Dalmatia, probably close to the provincial capital of Salona, which is between what is now Split and Trogir. He built a fort for his retirement on the Adriatic harbor of what is now Split (then Spalatum, the name for a white torn). This is called "Diocletian's Palace," but was and is a walled city, not a single building in which Diocletian lived. What was his actual residence (villa) is gone. What remains are the basement, what was the temple he consecrated to his patron, Jupiter, king of the gods, and what was his mausoleum. Stones from other buildings were recycled in medieval and later buildings within the walls of "the palace," and some of the Egyptian sculptures he had remain.

Rich Romans often repeated what was above ground under ground, cooler rooms to be used in hot weather. Moreover, fearful of assassination, Diocletian made sure he had an escape route directly onto a ship. Thus, the "basement" rooms are quite grandiose with ceilings about 20-feet above the floor. In medieval times, this level was filled with garbage that compacted and fossilized over the centuries and was forgotten until some British bombs during the Second World War revealed the lower level. After the war, it was excavated and is now open to visitors.