The collected works of botanist Carolus Clusius
Woodcut of Brazilian bean in C. Clusius, Exoticorum libri decem. Leiden: Officina Plantiniana, 1605. Shelfmark: KW 177 A 1 [3].
Tulips, runner beans, and potatoes. Dodos, birds of paradise, and sloths… These are just a few examples of the hundreds of plant and animal species described by the sixteenth-century botanist Carolus Clusius, often as the first. His collected works are held in the KB: a thick parchment volume that takes you on his discoveries through the plant kingdom.
Pioneer in plants
Carolus Clusius (1526–1609) was one of the greatest naturalists of his time. He is best known here as the first director of the Leiden botanical garden and as an expert and grower of bulbous plants from the Middle East, such as tulips, hyacinths, and crown imperials. In doing so, he laid the foundation for what would later develop into the famous Dutch tulip culture. But his story reaches further.
Clusius was one of the most prolific scholars of his time, a true humanist with broad interests, extensive linguistic knowledge, and a critical, inquisitive eye. He studied Roman tombstones, drew maps, and translated travel accounts. But his heart lay with nature, and especially with plants. From 1557, when his French translation of Dodoens’ Cruijdeboeck appeared, until his death in 1609, he published dozens of works in that field. Most were published by the famous printer Christoffel Plantijn (1520–1589) and his heirs in Antwerp and Leiden.
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Parchment binding with the collected works of Carolus Clusius. Shelfmark: KW 177 A 1.
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Jacques de Gheyn the Younger, portrait of Clusius as an old man, copper engraving, 1600. Shelfmark: KW 177 A 1
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Frontispiece of C. Clusius, Rariorum plantarum historia. Antwerp: I. Moretus, 1601. Shelfmark: KW 177 A 1 [1]
Compilation tape
The KB preserves many of Clusius’s books, but one stands out: a parchment volume approximately 30 centimeters high containing his collected works on nature. It includes, among others, Rariorum plantarum historia (Description of rare plants) from 1601 and Exoticorum libri decem (Ten books about exotica) from 1605. It also contains his posthumous notes, which were published posthumously as Curae posteriores (1611). Together, they form the collected works of the prolific botanist. As we leaf through the thick volume, we can follow Clusius on his lifelong journey of discovery through the plant kingdom.
This thick collected volume was part of the donation of more than 464 natural history books by G.A. Six to the KB in 1896. It must have been one of his showpieces and is fully annotated in a seventeenth-century hand.
Botanizing through Europe
Clusius was born in the Flemish city of Arras (now Arras, in northern France). After studying classical languages, law, and medicine, he devoted himself full-time to research into plants. In doing so, he proved himself a child of the so-called "botanical renaissance," a revival of scientific interest in plants. Physicians, pharmacists, and other scholars sought to improve their knowledge of medicinal herbs by comparing classical texts with what they themselves encountered in the wild.
Clusius borrowed their critical eye and empirical methods, but also went a step further: he was interested not only in medicinal herbs, but in all plants. In a Europe torn apart by religious conflict and wars, Clusius went in search of previously unknown plants. He wanted to map everything. Thus, he traveled on horseback to southern France, Spain, and Portugal to describe wild herbs. He also climbed the highest peaks in Austria to study mountain plants. Close to the border with the Ottoman Empire, he conducted research on mushrooms while Habsburg soldiers protected him. He published his field observations in richly illustrated books of a handy format. They are the precursors of modern floras, containing descriptions of wild plants from a specific area.
During his travels through Europe, Clusius also became acquainted with the many exotic plant species that merchants, diplomats, and soldiers brought back from their overseas voyages. Thus, in Spain and Portugal, he encountered unknown plants from the colonies in South America and Asia, such as the five-cactus, the tobacco plant, peppers, and jasmine. And in Vienna, he saw colorful tulips, hyacinths, and crown imperials from the Ottoman Empire blooming in the imperial ornamental gardens. Clusius was very successful in propagating this rare plant material in his own gardens, enabling him to publish new descriptions. His research and books made him famous. Wealthy garden owners asked him to beautify their gardens with exotic flowers, herbs, and fruit crops.
Exotica in Leiden
When Clusius finally received a permanent appointment at Leiden University in 1593 (at the age of 67), a happy time began for him. He was responsible for the first botanical garden in the Netherlands and taught students about plants. He was also given the peace and resources to work on new publications. Thus, in 1601, he published the first volume of his collected works on plants, Rariorum plantarum historia, in large format and with hundreds of woodcuts and a beautifully engraved frontispiece. It contained all his previously published and many new plant descriptions, as well as an appendix on mushrooms.
But Leiden offered him something else: access to new species. At that time, the young Republic was just entering the world stage and attempting to carve out a place for itself among the seafaring, trading, plundering, and warring powers. When the ships of the First Voyage returned from their journey to the Indies in 1597, the old botanist stood on the quay to question the crew. And when the VOC was founded in 1602, he sent instructions to the crew regarding the collection and preservation of plants. This yielded him a wealth of new information.
In 1605, the second volume of his magnum opus appeared, a thick book about hundreds of exotic plants and animals: Exoticorum libri decem. It contained all his knowledge of non-European flora and fauna that he had acquired during his many travels, but especially during his time in Leiden. Here we find the first scientific descriptions and illustrations of South American plant species such as potato and tobacco, but also armadillos, penguins, and sloths.
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Woodcuts of potato in C. Clusius, Exoticorum libri decem. Leiden: Officina Plantiniana, 1605. Shelfmark: KW 177 A 1 [3].
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Woodcuts of a sloth in C. Clusius, Exoticorum libri decem. Leiden: Officina Plantiniana, 1605. Shelfmark: KW 177 A 1 [3].
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Woodcuts of bird of paradise in C. Clusius, Exoticorum libri decem. Leiden: Officina Plantiniana, 1605. Shelfmark: KW 177 A 1 [3].
An example for others
Clusius worked strictly according to the rules of the empirical research method: he recorded only what he saw himself or what eyewitnesses told him. He never invented anything. That is why he had the beans and pods of unknown bean species from Africa and America depicted exactly as the sailors showed him, without inventing a plant or flower to accompany them. And he included an illustration of a legless bird of paradise from Indonesia, because these were always cut off by the local hunters who traded the birds with their beautiful plumage to the Dutch. His method often yielded incomplete information, but by gathering pieces, Clusius collected the puzzle pieces upon which later botanists would build.
References
- Dit artikel verscheen eerder in Bibliotheekblad 5, mei / juni 2026.
- Kasper van Ommen (red.), The exotic world of Carolus Clusius (1526-1609). Leiden: Leiden University Library, 2009.
- Esther van Gelder, Tussen hof en keizerskroon. Carolus Clusius en de ontwikkeling van de botanie aan Midden-Europese hoven, 1573-1593. Leiden: Leiden University Press, 2011.
