Tucked within the western section of Diocletian’s Palace, this compact Roman temple packs centuries of transformation into its limestone walls. Originally built between 295 and 305 AD, it was dedicated to Jupiter—the supreme deity of the Roman pantheon and Diocletian’s divine father. Its placement opposite the emperor’s mausoleum wasn’t accidental; it symbolized the ruler’s godlike status in life and death. Step inside and you’ll find a barrel-vaulted ceiling with intricate coffered patterns, a rare architectural feat for its time. Outside, a headless Egyptian sphinx guards the entrance, one of twelve brought from Egypt by Diocletian himself. Over the centuries, the temple was repurposed as a Christian baptistery, now housing a bronze statue of St. John the Baptist and sarcophagi of medieval archbishops. It’s a place where pagan grandeur meets Christian devotion, and where Split’s layered history is carved into every stone.