Diocletian was the first Roman Emperor to voluntarily retire. What modern city is closest to his retirement home?

From a humble birth, Diocletian rose through the military to become one of the greatest Roman emperors. He wrested the position from the Carinus, the son of the previous emperor Carus in 284 AD after the battle of the Margus and stabilized the empire, setting up one co-emperor and 2 junior emperors (the Tetrarchy). He remained in office until he retired for health reasons in 305 and lived 6 more years on the Dalmatian coast, dying at the age of 68. The modern city of Split, Croatia is built around his former palace.