Dvigrad is an abandoned mediaeval city containing the remains of 180 houses, well-preserved fortifications with square towers, and four city gates. The site was inhabited even in the Early Middle Ages, as indicated by the ruins of the Romanesque basilica of Saint Sophia in the centre of the city. Archaeologists have found that it was built over two earlier churches: an early Romanesque one and an early Christian church from the sixth–seventh centuries.