Gilding is the technique of applying thin sheets of gold leaf — beaten to near-translucency — or gold powder to a surface, typically wood, plaster, leather or metal. In medieval and Byzantine art, gilded backgrounds in icon painting and manuscript illumination were not merely decorative but theologically significant: gold represented the divine light of heaven, transcending the material world. The elaborate gilding of manuscript pages (chrysography — writing in gold) was a mark of devotion. In Renaissance altarpieces, gold backgrounds gradually gave way to painted landscapes as artists adopted perspective, but gilded frames and details persisted. The technique reached extraordinary elaboration in the Baroque — particularly in Austrian and German church interiors where gilded stucco covered entire vaults and walls. Gustav Klimt's 'golden phase' (1900–1907) revived gilding as a self-conscious return to Byzantine flatness and luxury.