The church was built on the ruins of a pagan temple of the god “Sole-Sorano” of 111 BC. A date of the year 1100 is engraved in the architrave of the portal. At that time the church was outside the walls. The building has undergone considerable vicissitudes. The Frederick had it destroyed in 1229 and rebuilt in 1250 according to his testamentary dispositions. A fire in 1916 destroyed the gilded ceiling and a valuable painting of Zuccari.
Of particular interest is undoubtedly the access portal work of Master Giovanni.
Attached to the cathedral there is the Bishop’s Palace of the XVI century and the Seminary, one of the oldest in Italy.
Inside the church there are two triptychs: one from the fifteenth century representing the Holy Trinity. The other Trinity, more recently, by the Norwegian artist Christian Mayer Ross.