On the night of 24 December 1734 the old Habsburg Alcázar burned down with the loss of exceptional paintings from the royal collection. The disaster, however, led to the construction of a new palace in the fashionable style of Italian classicism. The decoration planned for this centre of the Crown’s administration and for the rooms to be used by the monarch and his family made use of numerous paintings rescued from the fi re, which once again hung on the walls of the principal rooms. Of more interest to the artists associated with the recently founded Academia de Bellas Artes de San Fernando were the fresco schemes that decorated these rooms in a modern, Neo-classical aesthetic based on complex historical allegories and on the aspirations of the Spanish monarchy. The Prado has many of the oil sketches produced as preliminary designs or to be shown to the monarch for his approval. They range in style from the airy, illusionistic and colourful Rococo of Giaquinto and Tiepolo to the rigorous Neo-classicism inspired by Mengs, evident in Bayeu’s rigorously perfect scenes. This group of preliminary sketches also constitutes a new genre as their highly fi nished nature meant that they were prized as independent paintings by connoisseurs of the period, who acquired them to decorate the new, sophisticated private rooms found in large and small palaces of the period. Shown alongside these preparatory studies are others on religious subjects for frescoes in churches and cloisters or for altarpieces, including Maella’s beautiful composition for Toledo cathedral and those by Bayeu for the collegiate church at La Granja.