The Cathedral of Orvieto it was built during the period when the medieval Comune achieved its moment of maximum splendour. Works began during the ponteficate of Nicholas IV in 1290 and the first mass was celebrated on August 15th, 1297 by Boniface VIII. The first known builder is the Benedictine Fra Bevignate. In 1309 the architect Lorenzo Maitani, having taken over the works, created and modified the façate to three cusps and reinforced the cross vault with rampant arches. The façade in considered a typical example of Italian Gothic art. The frames of the cusps show various scenes from the life of Jesus and the Madonna with gilt mosaics that over the centuries have been restored and repaired. In the center of the façade, between the two central cusps, is the rose window, a masterpiece by Andrea di Cione better known as Orcagna. It is made up of small columns and delicate decorative elements, with the head of the Redeemer in the centre. It was built between 1354 - 1380. The three portals on the façade have great effect. The ones on the sides end in an ogive and the central one is round; the sloped surface is beautifully decorated with a series of small twisted columns alternated with decorative fascias. In 1970 the old wooden doors were replaced with bronze doors finished by Emilio Greco.