Editing Eugène Viollet-le-Duc (section)

==Doctrine==
Viollet-le-Duc famously defined restoration in volume eight of his ''Dictionnaire raisonné de l'architecture française du XI au XVI siecle'' of 1858: "To restore a building is not to maintain it, repair it or remake it: it is to re-establish it in a complete state which may never have existed at any given moment." He then explained that it had to meet four conditions: (1) The "re-establishment" had to be scientifically documented with plans and photographs and archeological records, which would guarantee exactness. (2) The restoration had to involve not just the appearance of the monument, or the effect that it produced, but also its structure; it had to use the most efficient means to assure the long life of the building, including using more solid materials, used more wisely. (3) the restoration had to exclude any modification contrary to obvious evidence; but the structure could be adapted to conform to more modern or rational uses and practices, which meant alterations to the original plan; and (4) The restoration should preserve older modifications made to the building, with the exception of those which compromised its stability or its conservation, or those which gravely violated the value of its historical presence.{{Sfn|Grodecki|1999|pages=710–711}}

He drew conclusions from medieval architecture that he applied to modern architecture. He noted that it was sometimes necessary to employ an iron frame in restoration to avoid the danger of fires, as long as the new structure was not heavier than the original, and kept the original balance of forces found in medieval structures. "The monuments of the Middle Ages were carefully calculated, and their organism is delicate. There is nothing in excess in their works, nothing useless. If you change one of the conditions of these organisms, you change all the others. Many people consider this a fault; for us, this is a quality which we too often neglect in our modern construction....Why should we build expensive walls two meters thick, if walls fifty centimeters thick [with reinforced supports], offer sufficient stability? In the structure of the Middle Ages, every portion of a work fulfilled a function and possessed an action."<ref>Viollet-le-Duc, Eugène, ''Dictionnaire raisonné de l'architecture française du XI au XVI siecle'' (1858)</ref>