The Cathedral was built in the 7th century over the great Temple of Athena (5th century BC). This was a Doric edifice with six columns on the short sides and 14 on the long ones: these can still be seen incorporated in the walls of the current church. The base of the Greek edifice had three steps. The interior of the church has a nave and two aisles. The roof of the nave is from Norman times, as well as the mosaics in the apses. The façade was rebuilt in 1725–1753.