Today, it's common knowledge that babies come from the union of egg and sperm. But this idea is fairly recent, the product of numerous discoveries spanning the 17th, 18th and 19th centuries. The basic concept that contributions from a man and a woman during sexual activity can lead to a baby, though, is much older -- and so are contraceptive barrier methods. For thousands of years, people around the world have used a variety of devices to physically keep these contributions away from each other. The two main historical contenders were pessaries, or objects placed in the vagina, and condoms.
Nowadays, pessaries are vaginal inserts that support a woman's pelvic organs when her muscles can no longer do so by themselves. But in many historical accounts, they had a clear contraceptive objective. There are also historical depictions of penile sheaths, but whether they had a prophylactic purpose is often unclear. The oldest known image of sheathed penis is found in cave paintings dating as far back as 15,000 B.C. [source: Allen]. Penile sheaths, garments and decorations also appear in the art and literature of ancient Egypt, Greece and India. In Japan, some men used thin, rigid sheaths called kabuto-gata, which were made from horns, during intercourse.
While people may have been using prophylactic condoms for much longer, there's not a lot of clear documentation on the topic until the time of the Roman Empire. Condoms were common in Europe by Shakespeare's day. The first documented condoms were hand-sewn pieces of linen that fit over either the entire penis, over the tip or into the urethra. A drawstringlike ribbon held the condom onto the penis during intercourse.
By the mid-1700s, people started using condoms made from animal membranes, still tied with a ribbon. Condom-makers -- many of whom also made gloves -- purchased intestines and bladders from butchers. Making guts into condoms required cleaning, scraping, exposure to burning sulfur, inflating, drying, molding, cutting and sewing.
These resulting prophylactics were expensive and often full of holes, which led to Casanova's famous technique of inflating them with air to test them before use. And like the first rubber condoms, their reliability was suspect -- and they were reusable.