Lorenzo Ghiberti's North Door of the Florence Baptistery(1403-24); detail, restoration process

Ghiberti’s doors changed over time exposed to climatic and historical vicissitudes. They were covered by wooden shutters to protect them in the eighteenth century; their golden surface was hidden under a greyish patina in the nineteenth century; they were removed during the Second World War, restored and again put in place in 1948; damaged by the flood of 1966. The North doors have suffered from centuries of pollution, which has greatly increased over the last decades. Their golden surface was nearly hidden for generations of visitors, but it is now being brought to light again through an ongoing restoration, thanks to the international patronage promoted by the Guild of the Dome.The long restoration of the Gates of Paradise has profoundly changed the methods of conservation of gilded bronze panels by means of new technologies and has set new international standards which are now being applied to the restoration of the first set of doors created by Ghiberti.