The art cities in the Marche boast splendid Cathedrals, full or works of art and Diocesan Museums with lots to see. The first and foremost among these is the Cathedral of Ancona, dedicated to St. Ciriaco, one of the most interesting medieval churches in Italy, where Romanesque style merges with Byzantine. Pesaro Cathedral has a stunning large mosaic floor dating from the mid 6th century AD. Fermo Cathedral, rebuilt by Frederick II, retains its imposing Romanesque-Gothic façade and an atrium filled with frescoes from the 14th Century. The Cathedral of St. Emidio, the patron saint of Ascoli Piceno and protector of earthquakes, is worthy of a visit especially for the crypt which houses the mausoleum with the Saint's body and a wonderful polyptych by Carlo Crivelli.