The Diocese of Poreč is one of the most ancient on the Adriatic. It was founded between the 3d and 4th century. Apart from the basilica, the architectural complex consists of a sacristy, a baptistry, an Episcopal residence, and a bell tower. It is one of the most valuable examples of Byzantine art in this region. The floor mosaics inside the church represents the early Christian symbol of fish. It remained intact until the present.