The protein which makes up the main three-dimensional fibrous network in a skin. It is found in stucco marble (Krzeszòw, Poland – late Baroque), which indicates that the glue used for the preparation of the stucco mass was obtained from collagen-containing materials, like fish, animal bones or skins. Trench (2000); Wittenburg (1999). [J. Cassar, R. de Angelis]