The construction of the present Duomo started after Spoleto was devastated by Frederick Barbarossa in 1155, and was completed between the 12th and the 13th century, when popes Innocent III in 1198 and Honorius III in 1216 solemnly consecrated the new building.
On the façade, embellished with the mosaic of master Solsterno in 1207, are the arches of the portico made in 1491 by Ambrogio Barocci da Milano below which is the beautiful main portal, finely carved with phytomorphic and zoomorphic motifs and signed by Gregorio Melioranzio, which can be read engraved on the left jamb.
Between 1638 and 1644 by the Barberini family's will, the interior of the cathedral underwent a radical transformation; the seventeenth-century intervention carried out by architects Luigi Arrigucci and Domenico Castelli completely overlapped the Romanesque structure but left unaltered the frescoes of the apse and the valuable mosaic floor with cosmatesque motifs of the nave composed of stone, porphyry and serpentine tiles, while that of the aisles in red and white lozenges was put in place in 1481. A further renovation carried out between 1785 and 1792 was directed by architect Giuseppe Valadier.
Inside the church are preserved precious works of art, such as the painted Crucifix signed and dated by Alberto Sotio in 1187 made on parchment applied to a shaped panel, in the iconography of the living Christ (triumphans) that developed in the 12th century in central Italy.
The apse is entirely decorated by the very beautiful frescoes portraying Stories of the Virgin, painted between 1467 and 1496 by Filippo Lippi.
The Chapels of Eroli and of the Assunta, with frescoes by Pinturicchio, are very important, such as the Chapel of the Relics, where St. Francis' autograph letter to Brother Leo is preserved, and the Chapel of the Holy Icon, with the precious tablet donated in 1185 by Emperor Frederick Barbarossa as a sign of peace.
