The Transfiguration was commissioned from Raphael by Cardinal Giulio de Medici, probably late in 1516, and was intended for his cathedral at Narbonne. Sebastiano del Piombo persuaded the Cardinal to commission a second, rival, altarpiece for the same location. The Transfiguration was completed just before Raphael died and was retained in Rome as a result of his unexpected death. It is now in the Musei Vaticani. Sebastiano’s picture was sent to Narbonne, and is now in the National Gallery, London. Raphael’s workshop was engaged to produce a replica of Raphael’s original, and this picture made its way to Spain in the seventeenth century. It is shown here with thirteen drawings that were produced by Raphael (and Giulio Romano) as Raphael planned the original painting and which were presumably available to Raphael’s workshop when they were working on this variant. Seventeen drawings, either originals or copies, are known for the Transfiguration and, as a result, one can trace its development in some detail. The sequence shows how Raphael realised that he could increase the drama of his picture by combining the Transfiguration with the appearance of the possessed boy to the apostles who have been left behind as Christ ascends Mount Tabor (the two episodes follow in the gospels, but no previous artist had combined them).