Contraceptives have existed for thousands of years. In ancient Greece and Rome, the use of a plant called silphium (found only in a small region of Libya) was so popular as a method of birth control that over-cultivation resulted in its extinction. In ancient Egypt, a concoction of crocodile dung (ew!) and sour milk was developed, which was then placed into the vagina to prevent pregnancy. You really do not want to get pregnant to come up with that!