Chartreuse (liqueur) was not a secret but well known. At the death of the pharmacist, his heirs returned the manuscript to the monks who had been back at the Monastery since 1816. In 1838, they developed Yellow Chartreuse, a sweeter version of the Green Chartreuse, 40% alcohol liqueur (80° proof). The monks were again expelled from the monastery following a French law in 1903, and their real property, including the distillery, was confiscated by the government. The monks took their secret recipe to their refuge in Tarragona, Catalonia, and began producing their liqueurs with the same label, but with an additional label
Portrait of a Carthusian the artist’s signature (the fly’s position right next to ‘Petrus ΧΡΙ Me Fecit’ hinting that the fly might be the referent of ‘me’ rather than the painting.) "Portrait of a Carthusian" featured a halo above the monk’s head when it was acquired by the Metropolitan Museum of Art in 1944. However, halos are extremely rare in Early Netherlandish painting and the one in "Portrait of a Carthusian" has long been an object of speculation. Finally in 1994, in preparation for the Met’s exhibition "Petrus Christus: Renaissance Master of Bruges", the authenticity of halo was publicly examined by a panel of