Orvieto rises on a natural tableland at the summit of a 150-metre-high tufa cliff emerging, much like an island, from the surrounding plains. The city's distinctive feature comes from the particular relationship between this sheer cliff and the fabric of the city dominated by its imposing cathedral.
Oriveto is of Etruscan origin with the more ancient traces dating back to 9th century BC; the necropolis and other findings indicate however, that the Etruscan settlement reached its peak development only between the 6th and 4th century BC and then declined in Roman times.
During the early Middle Ages, the cliff's strategic importance as a natural fortress was once more appreciated; a new settlement developed around the year 1000 and became a free Commune in 1137. At the centre of a vast territory, Orvieto's social, political and economical importance progressed rapidly, inducing important building activities - stately homes, towers and churches - and favouring the development of arts and crafts with the manufacture of refined handicrafts. The city reached its maximum expansion between the 13th and 14th century and its very particular urban structure has since remained basically unchanged.
Orography obviously conditioned the urban structure so that the city's perimeter coincides with the borders of the tableland. The city centre is laid out on an East-West axis and its development shows an interesting functional polycentrism, featuring two new axes, at right angles to the main one, leading to two new squares designed at the same time as the respective monuments (Piazza del Duomo and Piazza del Popolo) in addition to Palazzo Comunale's square in the ancient centre.
The Cathedral was built between the end of the 13th century and the first half of the 14th century and marks Orvieto's peak development. The new cathedral was titled to Santa Maria Assunta in Cielo and erected over the ruins of two other churches: the previous mother church and St. Costanzo. The works spanned several centuries and produced one of the more grandiose examples of Italian medieval architecture.
The facade, a great triptych built by Lorenzo Maitani in the first years of the 14th century, is certainly the prime masterpiece of Italian decorative Gothic. Superb mosaics on gilt backgrounds cover every surface free of architectural structures or bas-reliefs. The elegant, large rose window above the central portal was created by Orcagna between 1354 and 1380. Particularly significant in the sober, luminous interior, the chapel built by Andrea Pisano, around 1350 and paintings by Beato Angelico, Benozzo Gozzoli, Perugino and Luca Signorelli.
The "palazzo" surrounding the Cathedral are also noteworthy, namely those built for Pope Urban IV (1262 - 1264), Pope Gregory X (1272 - 1276) and Martin IV (1281 - 1284); they now appear as a single unit although the diverse typology of each one remains clearly identifiable.
The popes frequently took residence in Orvieto and this led also to the construction of Pope Boniface VIII's palazzo, known as Palazzo Soliano; it followed the rhythms of the Cathedral's construction and ended up as its annexe. Palazzo dell'Opera del Duomo was erected in 1359 to house the administration of the Cathedral's works; next to it, Palazzo Faina was built using the structure of the medieval Palazzo Monaldeschi and today houses the Archaeological Museum. The area was restructured in the 16th century in order to give more space and decorum to the Cathedral which then became the ideal centre of the city.
Political events during the Middle Ages were marked by the city's struggle against papal dominion but, in 1354, Cardinal Albornoz conquered Orvieto and submitted it to papal authority. The city managed, however, to maintain communal independence; it was ruled by several foreign feudal lords, then fell under the oppression of Gentile and Arrigo Monaldeschi and, finally, returned to the Church in 1450.
Following Cardinal Egidio Albornoz's diplomatic and military victory, it was established that, as in all other cities of the Papal States, a fortress would be built also in Orvieto, on the tableland's far eastern border. The first fortress, begun in 1364, was very probably designed by Ugolino di Montemarte, Albornoz's military architect, in cooperation with Giordano Orsini. It was quadrangular, protected by a moat with two draw-bridges, with a lodge next to the gateway and other utility buildings along the walls. This fortress was destroyed a few years after it had been completed (1390) and rebuilt by Antonio da Carpi (1450-1452) over the same perimeter with the addition of a circular ravelin; the construction was completed under the supervision of Bernardo Rossellino.
A first urban renewal took place throughout the 16th century when, over the ancient medieval structure, new churches and "palazzo" were built by celebrated architects including Michele Sammicheli, Antonio da Sangallo il Giovane, Simone Mosca, Raffaello da Montelupo and Ippolito Scalza from Oriveto whose contribution to the city's renewal was particularly significant.
A similar phenomenon occurred again during the 19th century when architects such as Giuseppe Valadier and Virginio Vespignani enriched the city with new, neo-classical public and private buildings
The wide range of styles found in the façades overlooking the typically medieval narrow streets is a measure of Orvieto's specificity, where renovation has not cancelled the traces of its long history.
The very particular geological characteristics of Orvieto's tableland also determined another of this city's specific features: the presence of an outstanding number of artificial caves dug out following the trend of the city's development. First of all the quarries that, in the course of the centuries, provided tufa, travertine, sand and "pozzolana" first for the Etruscan buildings and later for Medieval and Renaissance "palazzi". There are also several caves created in order to find, draw, store and distribute water; caves were also used as stables, cattle sheds, colombariums and to store grain. In some cases there are clear signs of the activities the caves were used for; searchers have found caves used for rope making, furnaces, potteries, wine cellars and oil mills. There is also a particular type of cave, known as butti, used as garbage dumps; this great mark of civilization dates back to the Middle Ages and there are several such caves under each house.
The celebrated Pozzo di San Patrizio or St. Patrick's well deserves special mention; it was commissioned by Pope Clement VII specially for Albornoz's fortress and built by Antonio da Sangallo il Giovane who was also in charge of the defences.
Sangallo took the idea from the Vatican's Chiocciola del Belvedere and created two one-way courses using a double helix pattern around a 53,15-metre-deep cylinder, more than half of it is dug out in the lithoidal tufa , the rest built in brickwork with 70 large windows to provide air and daylight.
Satements of authenticity and/or integrity
The proposed site fulfils the criteria for authenticity; both the urban structure and the architectural complexes are well preserved and, in the course of time, have been restored following strict philological criteria
City centres and single monuments come under the protection of national legislation concerning cultural heritage, (Decree n. 42/2004), regional regulations (landscaping regulations) and municipal regulations (zoning regulations), while the management procedure are aimed at ensuring their conservation.
Comparison with other similar properties
Orvieto can be distinguished from all the other cities that still show their original medieval structure in that the conscious symbiosis between the impressive tufa tableland and the overlying urban structure is such that the city, dominated by the Cathedral's mass, and its natural support form a single, very particular image.
Orvieto's Cathedral is the prime masterpiece of Italian decorative Gothic; a lesser formal linearity, the great variety of materials used, as well as the sumptuous and highly significant internal and external decorations, distinguishes it from all other European cathedrals.
The Cathedral is also a unique achievement in thirteenth-century Italy in that, with its references to classical architecture, it heralds the criteria that will be the bases of Renaissance architecture.