A sheet of metal with a repousee design from ancient Greece was analyzed. It consisted of a layer of copper bonded between two layers of a white metal. The excellent state of preservation of the thin sheet of metal is explained by its chemical composition. Though pure copper is resistant to natural agents of corrosion, copper alloys containing a high proportion of tin, such as the white alloy of this object, are much more resistant. This sheet of metal is of considerable historical interest as an example of a large plated ancient object. It seems possible that various large Greek and Roman metal objects, especially vessels of sheet metal, now on exhibition in museums, and which are now regarded as being composed of bronze or copper, may in fact be plated objects of various sorts.