The epistolary relations between Marie Bonaparte and Sigmund Freud, which began in 1925, lasted for more than thirteen years and consisted of nearly a thousand letters. Exuberant and overflowing with energy, Marie Bonaparte first wrote to Sigmund Freud in French, and he was soon intrigued by this resolutely modern and curious woman. Marie then switched to German, and then, in the course of her sessions, to the language of psychoanalysis (a method and body of thought that she contributed greatly to making known in France) and finally to that of trust and friendship.