 Freud's reports of the seduction theory episode went through a series of changes over the years, culminating in the traditional story based on his last account, in "New Introductory Lectures on Psychoanalysis".On the evening of April 21, 1896, Sigmund Freud presented a paper before his colleagues at the Society for Psychiatry and Neurology in Vienna, entitled "The Aetiology of Hysteria".Using a sample of 18 patients—male and female—from his practice, he concluded that all of them had been the victims of sexual assaults by various caretakers.