A natural red dye obtained from Rubia tinctorium, a perennial herb cultivated in Europe and Asia Minor. The cultivation of madder spread to Asia Minor about the 10th century; it was introduced into Europe by the 13th. The dye contains three principle colouring components: alizarin (red), purpurin (red) and xanthine (yellow). The colours are extracted from the dried, powdered root as a precipitate when it is boiled in water. Alum lakes of madder, madder lake and rose madder, were used as artists pigments. Madder forms a bright red colour when precipitated on aluminium hydroxide. Tin, chromium and iron mordants can produce purple, brown and pink colours. After commercial introduction of the synthetic alizarin in 1871, the natural product was no longer used, though natural rose madder was still used occasionally as a lake for artists' colours. Madder lake is listed among the pigments used for colouring stucco marble in the nineteenth and twentieth century. The presence of purpurin along with alizarin has been used to distinguish natural madder dyes from the synthetic alizarin dyes. Purpurin fluoresces a bright yellow-red while alizarin produces a pale violet colour. Synonyms: madder lake; alizarin (natural); purpurin (natural); xanthine (natural); garancine; Pigment Red 83; CI 58000:1; Natural Red 9; CI Nos. 75330, 75420; dyer's root; Farberröte (Ger.); Krapplack (Ger.); laque de garance (Fr.); lacca di robbia (Ital.); laca de rubia (Sp.); rose madder; Turkey red. Wittenburg (1999); Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]