De Monstris

Manuscripts of the Institut de France – Faksimile Verlag – mss A - M – Institut de France (Paris, France)

Padua (Italy) β€” 1668

Siamese twins, hybrids and "monsters": On the biological causes of physical malformations of humans and animals as a link between medieval conceptions of nature and modern science

  1. Fortunio Liceti initially published his treatise on physical deformities in 1616 without illustrations

  2. The author describes not only congenital deformities, but also wondrous mythical creatures and common animals from foreign regions

  3. The 1668 edition features 73 high-quality copper engravings and an eye-catching title page

De Monstris

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  1. Description
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De Monstris

With De Monstris, Fortunio Liceti made an important contribution to the history of medicine and science. The work, first published in 1616, made a major impact on the dissemination of innovative approaches to explaining physical deformities, which did not merely refer to supernatural fates, but rather sought for biological causes. The 1668 edition of the treatise, published by Paolo Frambotti in Padua, also features 74 high-quality copperplate engravings, probably created by Hendrik Bary. Based on the text, these show not only physical dysplasias, but also wondrous mythical creatures and 'exotic' animal species.

Ancient fascination

Accounts of deformities are as old as human written culture. Already in ancient Babylonia and Greece dysplasias of human bodies were described. Such non-standard body shapes were interpreted as a 'play of nature' or omen until the 16th century, which is why terms like 'monster' and 'monstrosity' were also common in this context.
In the early modern period, however, people were no longer pleased with purely supernatural explanations for the miraculous phenomena and began to search for their causes, which were initially assumed to be in the genome, mechanical impacts on the fetus, and diseases of the same. With the increased interest in the subject, the first publications concerning root cause analysis appeared in the 16th and 17th centuries, of which probably the most influential and widely circulated was Fortunio Liceti's (1577–1657) De Monstrorum Causis, Natura et Diferentiis.

A product of its time

Liceti initially published his most successful and best-known work in 1616 without any illustrations. His treatise, divided into two books and dozens of shorter chapters, however, not only deals with physical deformities in the modern sense, but also includes passages on wondrous mythical creatures and common animal species which were only perceived as exotic and 'abnormal' by the European readership.
Thus, the author linked two extremely popular and much discussed topics of his time. First, it is about the limits of (human) physiognomy and the related idea that the character of the soul is also reflected in the external appearance of the human being. According to this, a deformed physique was at the same time understood as evidence of moral weaknesses or even a corrupted soul, which is based on Pseudo-Aristotle's treatise Physiognomonica. On the other hand, the text is also influenced by the burgeoning Renaissance ethnography that developed from the increasing exploration of the world and the countless tales of the foreign. The growing interest in the inhabitants of non-European regions was accompanied by many prejudices about these 'others', who were subsequently often imagined as 'monsters' or people with physical 'monstrosities'.
Accordingly, Fortunio Liceti's work hit exactly the taste of the time and its widespread reception soon allowed for several (illustrated) reprints, which appeared under the shorter title De Monstris.

Astonishing illustrations

Thus, 1634 saw the first illustrated edition of the text, to which initially 58 copper engravings were added for this purpose, which served as models for later editions. Among these, the one that stands out the most is the edition published 1668 by the printer Paolo Frambotti in Padua and dedicated to the couple VeritΓ  and Girolamo Zenobio from an important Veronese family. Its quality and meticulous decoration with fantastic copper engravings immediately catches the eye. The edition, published posthumously by Gerardus Leonardus Blasius (d. 1692), was supplemented by the latter with an Appendix, which additionally contains 15 new illustrations showing famous contemporary cases of malformed bodies that had become known after the dissemination of Liceti's work. The edition is also complemented by a striking title page with a wonderful full-page copper engraving signed by Hendrik Bary (d. 1717), who was probably also responsible for the rest of the illustrations.

A piece of medical and scientific history

Although the work remains attached to Aristotelian doctrines and thus to some assumptions and beliefs of antiquity and the Middle Ages, it nevertheless represents an important step in medical history, as it disseminated new theses on the causes of malformations. This approach, which was quite innovative at the time, and the search for biological explanations as a counterweight to the supernatural attempts at explanation of earlier times makes De Monstris an important work in the history of medicine and science. Together with similar treatises, it forms the foundation of modern scientific teratology.


Alternative Titles
De monstrorum causis
Size / Format
356 pages / 19.0 Γ— 15.0 cm
74 copperplate illustrations, including one title page
Treatise on physical deformities among humans and animals
Artist / School

Available facsimile editions:
Manuscripts of the Institut de France – Faksimile Verlag – mss A - M – Institut de France (Paris, France)
SiloΓ©, arte y bibliofilia – Burgos, 2022
Limited Edition: 898 copies
Detail Picture

De Monstris

The Monster from the Tiber

This copperplate engraving shows three exceptional hybrids, which surpass even ancient and medieval imaginations and myths. The creature on the right is said to have been discovered in the Tiber River in Rome in 1496, according to the text. The depiction corresponds to the description above: The female-shaped body is mostly covered with scales, while the head resembles that of a donkey. The extremities all have different ends - thus the monster has a human hand, an arm stump in the shape of an elephant's foot, a foot with eagle claws and a cloven hoof.

Manuscripts of the Institut de France – Faksimile Verlag – mss A - M – Institut de France (Paris, France)
Single Page

De Monstris

Lazarus and Joannes Baptista Colloredo

The two brothers Lazarus and Joannes Baptista Colloredo were probably the most famous Siamese twins in 17th century Europe. The twins, fused at the abdomen or chest, were born in 1617 into a wealthy Genoese family and were already examined in infancy by various physicians who sought to understand the phenomenon. In the adulthood Lazarus decided to exhibit himself and his brother in numerous European countries, whereby the two could afford a respectable life-style.

That is reflected also in this illustration: The upright standing Lazarus carries an expensive coat over shirt and trousers. The right hand is thereby pressed into the side, which lends to him steadfastness. His brother Joannes Baptista hangs passively and half dressed at his front, while the two arms seem to reach for parts of the clothing and he supports his only foot at Lazarus' knee.

Manuscripts of the Institut de France – Faksimile Verlag – mss A - M – Institut de France (Paris, France)
Facsimile Editions

#1 De Monstris

SiloΓ©, arte y bibliofilia – Burgos, 2022

Publisher: SiloΓ©, arte y bibliofilia – Burgos, 2022
Limited Edition: 898 copies
Binding: The hand-bound facsimile comes in a protective slipcase.
Commentary: 1 volume
Language: Spanish
1 volume: Exact reproduction of the original document (extent, color and size) Reproduction of the entire original document as detailed as possible (scope, format, colors). The binding may not correspond to the original or current document binding.
Facsimile Copy Available!
Price Category: €€
(1,000€ - 3,000€)
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