The frescoes that decorate the time of the Sacristy of the Mansionari are made by the “Morazzone” between 1611 and 1612. The execution technique of the painted parts turns out to be, in the great majority, fresco. The state of conservation of the paintings presented different deteriorations, as well as detachings, swellings and pulverisation of the pictorial film, while the one of the stuccoes reflected the bad environmental conditions it had suffered and significant deteriorations owed to water infiltrations. The losses were obvious also on the gilding that, like the stuccoes, had been the subject of different interventions of restoration roughly carried out. The stone facing of the windows was, as the walls, covered by a thick soot layer. Several analyses have been carried out and, as well as having identified repainting, they have have noted the lack of any trace of dirt between them and the original painting, which was confirming the energic cleanings that have abraded the pictorial surface and that later required coatings. To clean the frescoes were used mainly very bland mixtures of ammonium carbonate in distilled water. The zones struck by saline efflorescences instead have been subject to long and numerous hydroalcoholic wraps. The old stuccos have been removed since they were not well anchored on their support, while the lacunas have been levelled and then pictorially reintegrated watercolours and the revealed zones have been lowered in their colour tone to restore the volumes of the clouds and the movement of the draperies. The preliminary treatment of the walls and the painting applied in triplicate coat with silicate paints have completed the intervention.