precious works of art in the church, the high altar. It consists of a 4th-century Roman-Palaeochristian sarcophagus with seven niches which are decorated by biblical episodes. At the end of the presbytery, over the wooden choir, is a canvas by Pietro Nelli (Annunciation), while at the sides are two frescoes of the Resurrection of John and the Martyrdom of Sts. John and Marcianus. A door on the left side of the presbytery leads to the oratory of Mary's Heart, built as a chapel in the 14th century. This houses important medieval works including: several 12th-century frescoes depicting a Madonna with Saints, an Angel and other Saints the front section of an early Middle Ages (9th-century) sarcophagus with representations of hunting scenes two Cosmatesque parapets flanked by two lions, originally in the cathedral's presbytery, dated to c. 1231-1240. Under the presbytery is the crypt, with cross-vaults, dating to the 12th century but renewed later. It houses two Renaissance marble cyboria, originally in the presbytery but walled here during the 18th-century renovation works. Sources External links Page at www.medioevo.org, with detailed images Churches completed in 1210 12th-century Roman Catholic church buildings in Italy Civita Castellana Churches in the province of Viterbo Cathedrals in Lazio Romanesque architecture in Lazio