Saint Domnius was a 4th-century bishop of Salona, a major Roman city in the province of Dalmatia. Born in Antioch to a wealthy family, he served as a religious leader during the persecutions of Emperor Diocletian. He is remembered as a martyr who died in 304, alongside several others who had been converted by his teachings. Today, he is widely recognized as the patron saint of Split, the modern city that succeeded Salona.