Toni Anna Wolff (18 September 1888 – 21 March 1953) was a Swiss Jungian analyst and a close collaborator of Carl Jung. During her analytic career Wolff published relatively little under her own name, but she helped Jung identify, define, and name some of his best-known concepts, including anima, animus, and persona, as well as the theory of the psychological types. Her best-known paper is an essay on four "types" or aspects of the feminine psyche: the Amazon, the Mother, the Hetaira, and the Medial (or mediumistic) Woman. Wolff was born in 1888, the eldest of three daughters of a wealthy Zurich family. Encouraged by her parents to pursue creative interests, Wolff developed a passion for philosophy and mythology, as well as for astrology. However, when she asked to be allowed a university education, her father denied her request, explaining that it was not appropriate for a young woman of her class to have an "official" education. Wolff pursued her studies by enrolling in classes as a non-matriculating student. In December 1909, when she was 21, Wolff's father died, and she became acutely depressed. She entered analysis with Jung on 20 September 1910, and almost immediately he was impressed by her intellect. Irene Champernowne, who knew both Wolff and Jung, testifies that Wolff possessed "remarkable insight and was articulate and confident." Jung treated her depression by stimulating and encouraging her to use her mind. She became one of "a long line of women who gravitated to Jung because he allowed them to use their intellectual interests and abilities in the service of analytical psychology". Wolff assisted Jung with research and accompanied him and his wife, Emma, along with a group of other colleagues, to a psychoanalytic conference in Weimar, Germany, in 1911; at that time Jung described Wolff in a letter to Freud as "a new discovery of mine, Frl. Antonia Wolff, a remarkable intellect with excellent feeling for religion and philosophy". Jung discharged Wolff from his analytic care around the end of 1911, despite his growing feeling of "being involved with her".