Peristil Square is Split's main square, the former entry hall in Diocletian's Palace. It is derived from a Roman architectural term called the peristyle, an open colonnade surrounding a court.
The spacious central courtyard is flanked by marble columns topped with Corinthian capitals and richly ornamented cornices linked by arches. There are six columns on both the east and west sides, and four more at the south end, which mark the monumental entrance to the Vestibul. Most of the structure is made of white stone from the nearby island of Brač; however, the columns are made of Italian marble and siennite from Egypt.
The Vestibul is a cavernous open dome above the ground floor passageway; a foyer that leads you into the emperor's residential quarters. The Vestibul provides great acoustics allowing klapa bands to perform traditional a capella songs there in the mornings.
The head of Peristil, the prothyron, connecting the public square to the private quarters was the only place a commoner would see the emperor as he addressed his people. On either side of the prothyron you will find a little chapel stemming from far after the time of Diocletian; Our Lady of the Belt (1544) and Our Lady of Conception (1650). Note the black granite sphinx standing guard outside the cathedral. It was one of 11 acquired by Diocletian during battle in Egypt.
Peristil is the host to various events through the year most notably the Split Summer Festival where the square converts into an open-air opera theatre. On May 7, the feast of St. Dominus is celebrated here. Occasional live concerts are also held here. During the day, the ruins and cathedral coexist with boutique hotels, shops, cafes and bars blasting live music at night.