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Banner containing six icons that link to the individual pages of the website.  From left to right: 1. Image of three embryos, that links to the Embryology page.  2. Image of conjoined twins from a 15th century book, that links to the Age of Superstition page. 3. Image of Millie-Christine McCoy, that links to the Marvels on Exhibit page. 4. Image of Clara and Alta Rodriguez, that links to the Separation Surgeries page.  5. Image of a fine engraving of two sets of conjoined twins, that links to the Gallery of Images page.  6. Image of a title page, that links to the bibliography page.   Below the banner, to the left of the links to each page is a large eighteenth century woodcut illustration of female twins joined at the back. From 'Monsters' to Modern Medical Miracles: selected moments in the history of conjoined twins from medieval to modern times. Embryology and Classification of Conjoined Twins Age of Superstition Marvels on Exhibit Separation Surgeries Gallery of Images Bibliography

Age of Superstition (15th through 18th-centuries)

From medieval times through the Enlightenment conjoined twins were viewed as monsters. Their existence simultaneously horrified and amazed the common person. The established medical explanation of the day, from Hippocrates, reasoned that a conjoined twin was simply the result of there being too much seed available at conception for just one child, but not enough for two distinct beings. Even so, popular theories fueled the public's fear and wonder by suggesting that conjoined twins were the result of impure conception or the witnessing of some evil or traumatic event during pregnancy.

Books depicting all sorts of monsters, both real and imagined, were extremely popular among the literate during this period. The authors often copied extensively from each other, bringing long told tales with new illustrations to another generation of the fascinated. Images of conjoined twins from some of the more popular works by Jacob Locher, Fortunio Liceti, the respected surgeon Ambroise Paré, and the anonymous author of Aristotle's Compleat Masterpiece are displayed below.

Fifteenth century woodcut illustration of female twins joined at the chest.

Locher, Jacob, 1471-1528. Carmen heroicum de partu monstrifero. Ingolstadt: Johann Kachelofen, after 26 Nov. 1499.

One of the earliest printed illustrations of a set of conjoined twins and the earliest printed work devoted entirely to the subject. The crude woodcut depicts thoracopagus twins, i.e. twins joined at the chest. The inset shows the bands of tissue and shared organs uniting the twins.


Sixteenth century woodcut illustration of female twins joined at the back.

Paré, Ambroise, 1510?-1590. Deux livres de chirurgie. Paris: André Wechel, 1573.

Although there were many 16th-century treatises on monsters, surgeon Ambroise Paré brought a more scientific approach to the genre in his treatise, Des monstres et prodiges. His descriptions of malformed humans and animal-human hybrids avoided fantastical stories in favor of simple realistic statements. His work became "the" monster book of the Renaissance.

This woodcut illustration depicts two unnamed female pygopagus conjoined twins who lived in Verona, Italy, circa 1475. Paré informs the reader that they were joined at the posterior, from the shoulders to the buttocks and shared their kidneys. Their parents earned money by exhibiting the pair in various Italian cities to people "who were burning to see this new spectacle".

Seventeenth century engraved illustration showing two views of female ischiopagus conjoined twins joined in the genito-urinary area.

Liceti, Fortunio, 1577-1657. De monstrorum caussis, natura, et differentiis libri duo. Patavii: Apud Paulum Frambottum, 1634.

An early classification of deformities, this is the first illustrated edition of Fortunio Liceti's work, originally published in 1616. It includes many firsthand descriptions made by Liceti himself.

This wood engraving depicts two cases reported in 1572 of ischiopagus conjoined twins joined in the genito-urinary area. Liceti reports that the girls shared one abdomen and one set of reproductive organs.

Untitled engraving from:  Liceti, Fortunio, 1577-1657. De monstrorum caussis, natura, et differentiis libri duo. Patavii: Apud Paulum Frambottum, 1634, p. 90.  Courtesy National Library of Medicine (NLM UI 2186006R)

Aristotle, pseud. Aristotle's compleat master piece, in three parts. The 29th ed. London: Printed and sold by the booksellers, 1772.

Originally published in 1684, this extremely popular work on generation and sexual reproduction was still being printed well into the 19th century. Amid the tales of monstrous births due to the mother witnessing traumatic events or having evil thoughts, is a report on the female pygopagus twins depicted here. Amazingly, the author tells the reader that one twin outlived the other by three years, only to succumb to death itself from the burden of having to carry the corpse around with it!