Sassari’s principal cathedral dazzles with its 18th-century baroque facade, a giddy free-for-all of statues, reliefs, friezes and busts. It's all a front, though, because inside the cathedral reverts to its true Gothic character. The facade masks a late 15th-century Catalan Gothic body, which was itself built over an earlier Romanesque church. Little remains of this, except for the 13th-century bell tower.

Of note inside are the frescoes in the left transept and the Gothic fresco in the second chapel on the right. Also in this chapel is a fine painting of the Martirio dei SS Cosma e Damiano (Martyrdom of Saints Cosimo and Damien), attributed to the 17th-century artist Carlo Maratta.