In the past, conservation of stone sculptures was understood to mean that repairs and reconstructions were acceptable since they aimed at maintenance, at offsetting weather-induced damage, and at prolonging the good aspect and stability of the works. Periodical upkeep of all statues outside of churches and palaces is documented. Materials used, as well as the color finish they received, are described. The kinds of treatments applied are presented and a long section covers the techniques of execution: 1) the careful selection of appropriate replacement materials; 2) the adhesives; 3) the final touches; 4) the application of an artificial patina whose ingredients are noted followed by encaustic coatings. The author discusses the causes and effects of aging and atmospheric pollution as described in the literature of the past and compares it with present-day conditions, introducing the age of scientific discoveries which has made possible the modern concept of conservation characterized by the necessity -- once the basic nucleus of the work has been defined -- to consolidate it. -- AATA