Casanova claimed to be a Rosicrucian and an alchemist, aptitudes which made him popular with some of the most prominent figures of the era, among them Madame de Pompadour, Count de Saint-Germain, d'Alembert, and Jean-Jacques Rousseau. So popular was alchemy among the nobles, particularly the search for the "philosopher's stone", that Casanova was highly sought after for his supposed knowledge, and he profited handsomely.[52] He met his match, however, in the Count de Saint-Germain: "This very singular man, born to be the most barefaced of all imposters, declared with impunity, with a casual air, that he was three hundred years old, that he possessed the universal medicine, that he made anything he liked from nature, that he created diamonds."[53]