The technique of majolica with “metallic lustres” arrived in the Mediterranean basin via the Arabic and Christian commercial routes, opened up by the maritime republics and by the crusades. They had a significant influence on the Italian production of ceramics in the Middle Ages. It arrived in Italy from Spain via ships from Majorca, hence the name majolica, which landed in the Tuscan ports. The precious “lustreware” became famous and the Umbrian potters were the principal manufacturers of very fine quality ceramics. The metal lustres are special chromatic effects of the ceramics. They can be more or less iridescent and change significantly depending on the type of light the piece is subjected to. Lustre decoration was obtained by applying an impasto of metal salts (known as “biscotto”) over the surface of the ceramic object. A second firing at a temperature of 850°- 950° glazed it and made it watertight. A brush was used to cover the object with an impasto to which oxides and metal salts, such as copper, manganese, cobalt and iron, had been added and blended with water or vinegar .. It was then replaced in the kiln (the so-called “muffle” kiln) for a third firing at a low temperature of approximately 650° C, in a reducing atmosphere, where they burnt smoke-producing substances (wood, sugar, broom, etc.). The objects were placed in such a way as to allow the smoke to circulate freely. The production of smoke decreased the oxygen level and enabled the oxides to transform into metal. The fine particles of metal blended into the melted glaze to give the ever-changing effect of the lustre. After firing and a slow cooling process, the object was cleaned. And the remains of the impasto and smoke were removed from the surface to allow the lustre to shine through.