Plaster cast

Usually very elaborate moulds were made out of several to even dozens of pieces, to cast the more difficult undercut sculptures.

The practice of reproducing famous sculptures in plaster originally dates back to the sixteenth century when Leone Leoni assembled a collection of casts in Milan.

Use of such casts was particularly prevalent among classicists of the 18th and 19th centuries, and by 1800 there were extensive collections in Berlin, Paris, Vienna and elsewhere.

These casts could also be used in experiments in polychromy (reconstructing paint layers found on sculptures), reconstruction (e.g. Adolf Furtwängler's reconstruction of the Lemnian Athena from pieces found in different places), and for filling holes in a museum's collections of actual sculpture (e.g. the British Museum sent casts of some of its Mesopotamian collection to the Louvre in return for a cast of the Louvre's Code of Hammurabi).

The technique was also applied later that century to reliefs from Ancient Egypt and friezes from Mesopotamia (examples of both of which may be seen on the North-East Staircase and in Room 52 of the British Museum), as well as to medieval and Renaissance sculptures (as may be seen in the Cast Courts at the Victoria and Albert Museum, which were a product of growing interest in medieval art at that time and the resulting desire to have a "reference collection" of such art).