 Complete the following phrase:  The slow process of transferring the murals onto canvas began in 1874. The walls of the villa had been covered in wallpaper and Goya had painted on top of this layer which was carefully removed and reapplied to canvas. This work was carried out under the supervision of Salvador Martínez Cubells at the request of Baron Émile dErlanger, a French banker of German origins, who wanted to sell them at the 