This majestic church dominates the eponymous square. It has Byzantine origins in AD 961, was converted to a Catholic church by the Venetians and turned into a mosque by the Ottomans, who also rebuilt it after the devastating 1856 earthquake. It has been an Orthodox church since 1925. Since 1966, it has once again sheltered the much-prized skull relic of St Titus, returned here after being spirited to Venice for safe-keeping during the Turkish occupation.