|from a Latin copy of Gynæcology by Soranus of Ephesus|
It seems to have started with Hippocrates (c.460-c.370 BCE), who maintained that men and women had entirely different bodies: men's humors were hot and dry by nature, women's were wet and cold. Women also had different processes, such as menstruation. Hippocrates did not pass judgment on these differences; they merely needed to be addressed by the practitioner of medicine.
Aristotle (384-322 BCE), however, had other ideas. He postulated that processes like menstruation could be harmful to men, who should avoid women during that time. He also felt men's bodies were perfect and women's were flawed. Women were irrational and unbalanced—literally "unbalanced," because he believed that the uterus "wandered" in the body.
By the time medieval medicine came along, the authority of Aristotle made it clear: over-emotional women were suffering from being unbalanced because of their womb. Hysteria could be treated by removing the source of the unbalance, and the hysterectomy was "born." (Sorry.) Unfortunately, as summarized in this abstract:
The procedure was performed by Soranus of Ephesus 120 years after the birth of Christ, and the many reports of its use in the middle ages were nearly always for the extirpation of an inverted uterus and the patients rarely survived. [source]The procedure wasn't considered remotely safe until antiseptic techniques began in the 19th century. Even so, it wasn't until the 20th century that diagnoses of hysteria declined, possibly because the general public came to understand that "hysteria" was too easily used as a label for anxiety.