So little consideration is given in early medical writings to sexual disorders, that it seems that these were, for many centuries, hardly regarded as the concern of the physician. There are a few exceptions. For example: Hippocrates (Airs, Waters, Places XVII-XXII) discussed the part played by constitutional and environmental factors in the causation of impotence among the Scythians. Later, Caelius Aurelianus, according to Zilboorg (1941), while expressing disgust at the debauchery which characterized Imperial Rome, seems to have recognized that sexual perversions were illnesses which, at times, were epidemic in character. Subsequently, and in particular during medieval times, problems of this nature seem to have had a moral rather than a medical connotation. Indeed it was not until towards the close of the nineteenth century that any real insight into the medico-psychological nature of sexual difficulties and deviations became apparent. This new awareness reached its peak following the investigations of Havelock Ellis, Freud, Stekel and others, and the formulation of certain psychoanalytic hypotheses.