Bronze is the name given to the alloy of copper and tin, when these chemical elements are combined at a ratio of roughly 9:1, respectively. However, the bronze used for making sculptural casts has often contained other metals and impurities. For example, Italian Renaissance bronzes, such as the Florentine Seated Lion and the medal of Francesco II Novello da Carrara often contain zinc, lead, silver, nickel, antimony and arsenic. This alchemic combination of metals creates an alloy with a high tensile strength, that can be cast into sculptural forms that are highly complex and (until fairly recently) could not be realised in any other material, particularly on a large scale. This, combined with its durability, has made bronze an appropriate and popular material for public statuary, as well as for smaller works. Its relative hardiness has also meant it was historically used for the production of tools, weapons and utilitarian objects, such as our Roman Casserole Patera, Bronze Age Axe Head, or the Short Sword with blood channels from Luristan.