It took them about ten years to finish. This series of frescoes were the largest in Italy at that time. They have been restored every hundred years for several following centuries. Two scenes, the "Annunciation" and the "Visitation", were redone by Antonio del Massaro at the end of the 15th century. The "Cappella del Corporale" lies on the north side of the main crossing. It was built between 1350 and 1356 to house the stained corporal of the miracle of Bolsena. It is from this chapel that the reliquary with the corporal is carried in religious processions through the town on the Feast of Corpus Christi. The chapel is two bays deep and covered with quadripartite vaults. It is closed off by a wrought iron gate, made between 1355 and 1362 by Matteo di Ugolino da Bologna and finished by Giovanni de Micheluccio da Orvieto in 1364. The chapel is decorated with frescoes depicting on the left wall the history of the Eucharist and on the right wall miracles concerning the bleeding host throughout church history. They were painted between 1357 and 1363 by three artists from Orvieto: Ugolino di Prete Ilario, Domenico di Meo and Giovanni di Buccio Leonardelli. They were painted prior to the frescoes in the apse. They were restored in the middle of the 19th century. The aedicule-shaped tabernacle on the altar was designed in 1358 by Nicola da Siena and finished by Orcagna. In a niche on the right wall stands a panel of the "Madonna dei Raccomandati" (c. 1320). It was painted in the Italian Byzantine tradition by the Sienese artist Lippo Memmi, brother-in-law of Simone Martini. At the centre of the chapel is the Reliquary of the Santo Corporale in silver, gilded silver and varicoloured translucent enamel containing the bloodstained corporal. This Gothic masterpiece, in the form of a triptych, was made by Sienese goldsmith Ugolino di Vieri between 1337 and 1338. It shows 24 scenes of the life of Christ and eight stories about the corporal. Although it largely goes wholly unnoticed today, the chapel also contains the reason millions of pilgrims came to Orvieto even before the occurrence of the Bolsena miracle and the construction of the cathedral: the tomb of St. Pietro Parenzo.