Characterization of the organic materials used in the painting of the vaulted ceiling at the Saadian Tomb of Mulay Ahmed Al-Mansour (Marrakech)

The Saadian tombs from the era of sultan Ahmed al-Mansour (1574–1603) are beautifully decorated andhave always been a major attraction for visitors to Marrakesh. The central mausoleum, named the Hallof Twelve Columns, encloses the tombs of Ahmed al-Mansour and his family. The hall has a huge vaultedceiling, carved cedar doors, opening windows with wooden marquetry screen (Mashrabiya), and greyItalian marble columns. This paper presents the first attempt to identify the organic materials used bythe Moroccan artisans. A GC/MS analytical procedure was used for the characterization of lipids, waxes,resins, pitch, tar, proteinaceous and saccharide materials in the same paint micro-sample. The analyticalstudy identified the organic materials used in the polychrome and gilded decorations of the walls, ceilingand dome of the hall. Data showed that the polychrome decorations were painted using animal glueas a binder, and highlighted the treatment of the wall surface with linseed oil and the retouching ofthe paintings based on a saccharide binder. The use of a proteinaceous-resinous-oil mixture, applied ona proteinaceous preparation layer, for the gilded decorations revealed a very similar technique to thatused at the time in Europe for mural paintings