It was in January 1592 that a large sealed package arrived at the lodging house where Clusius was living. It was a letter from Marie de Brimeu containing the news that he had been offered a post in the medical faculty of the University of Leiden.

Leiden was a large industrial town in the United Provinces of the Netherlands—not a place that Clusius would normally have chosen to live. But de Brimeu’s letter arrived at a particularly opportune moment. After leaving Vienna, the old botanist had retreated to Frankfurt to be close to his friend and patron, the landgrave of Hesse. But the landgrave had just died, his heir had canceled the small yearly pension on which Clusius relied, and deprived of his principal source of income, he badly needed to find work. The post at Leiden offered not just recognition of his life’s work but a salary of 750 guilders a year plus his travel expenses; in addition, several of his correspondents already worked at the university, and the man who had actually proposed him for a professorship, Johan van Hoghelande, was a friend with whom he had exchanged flower bulbs for years. After some consideration, and not without reluctance, Clusius decided to accept van Hoghelande’s offer.

Thus it was that the man who had done more than anyone to popularize the tulip made his way to the Dutch Republic, where the flower would become truly famous. Clusius reached Leiden on October 19, 1593, bringing with him many of his precious plants. Among his baggage was his extensive—and by now quite valuable—collection of tulip bulbs.

The botanist’s new home was a substantial town of perhaps twenty thousand people that stood more or less in the center of the United Provinces. The city was built around the ruins of a medieval castle and was noted as a busy center of the textile trade. Yet when Clusius arrived there, civic confidence was in a fragile state. Leiden might have been a large town by Dutch standards, and the university was its pride and joy, but the town was only just emerging from a century of stagnation to embark on a period of rapid expansion that would culminate in its becoming one of the two biggest cloth towns in Christendom. Really there seemed to be no reason why anyone who lived outside Holland should have known or cared much about it. Yet as Clusius himself would have been well aware, in the closing years of the sixteenth century Leiden was actually one of the most celebrated places in Europe.

The town’s fame rested on the heroic role it had played in one of the defining events of the century: the Dutch Revolt. For much of the sixteenth century all seventeen provinces that made up the Low Countries—both the south, which is now Belgium, and the north, which became the United Provinces and is now the Netherlands—were among the ancestral lands of the king of Spain. The king (and between 1556 and 1598 it was the same Philip II who loosed the Spanish Armada on England) was the most powerful monarch in Europe, controlling a world empire that already included much of South and Central America. He was fighting the Turks in the Mediterranean and the English in the Caribbean, as well as confronting the French in Europe. The southern provinces of the Netherlands were centers of commerce and important strategically in any conflict with France, but the lands to the north were a long way down on Spain’s list of priorities. Certainly the king was disinclined to listen to protests from the Netherlands about the high rates of tax being imposed to pay for his wars or the presence of large numbers of Spanish troops there who were being fed and watered at Dutch expense. As a fervent Catholic, he was even less willing to tolerate the rise of Protestantism in his possessions, and from the 1550s there was considerable persecution of the new religion throughout the seventeen provinces.

By the 1570s popular feeling was running against Spain in many parts of the Netherlands, but particularly in the seven predominantly Protestant provinces that lay to the north of the rivers Waal and Maas. These provinces—they were Holland, Zeeland, Gelderland, Utrecht, Groningen, Overijssel, and Friesland—were poorer than their ten brothers in the south, but they occupied lands that were difficult to attack. When open revolt finally broke out in 1572, even the vaunted armies of Spain proved incapable of conquering them.

The spark for the revolt was provided, inadvertently, by Queen Elizabeth of England. For several years she had been harboring a group of Protestant Dutch pirates known as the Sea Beggars in her Channel ports. Under pressure from Spain she finally expelled them in April 1572, and with nowhere else to go, the Beggars went marauding along the Netherlands coast until they came upon the little port of Brill. Discovering that it had been temporarily left without its Spanish garrison, they occupied the town, to the general acclaim of its inhabitants. Five days later the Beggars sailed down the Zeeland coast and seized Flushing, a strategically vital port that among other things controlled Antwerp’s access to the sea.

From there revolt spread quickly across the Netherlands. By July almost the whole of the province of Holland, with the exception of Amsterdam, was in the hands of the rebels. At Leiden popular opinion was so in favor of the Beggars that the town went over to the revolt spontaneously, before any Protestant troops could be sent to form a garrison. The citizens of the town chased out the few loyalists there, then thoroughly pillaged the Catholic churches, thus earning the undying enmity of the Spaniards.

One of those who reacted most quickly to the news of the uprising was William the Silent, the Calvinist prince of Orange, who soon became the main figurehead of the revolt. He had himself proclaimed stadholder—a title roughly equivalent to governor—of Holland and then “protector” of the Netherlands as a whole. Before long William had put himself at the head of a substantial army and was preparing to resist the inevitable Spanish counterstroke.

It came before the end of the year, and when it did, the Spaniards showed that their strategy was to terrorize the Dutch into submission. Several small towns were overrun and their citizens massacred, sometimes almost to a man. Fear of the Spanish terror cowed many of the cities that had declared for a republic, and before long only the provinces of Holland and Zeeland remained committed to the revolt. A huge Spanish army gathered to push north into the last rebel territories and snuff out the rebellion. Standing in its way was Leiden.

The siege of Leiden was the hardest fought, the costliest, and the most decisive of all the actions of the revolt. Had the town fallen, the Spaniards probably would have succeeded in mopping up the remaining Dutch resistance and restoring their rule throughout the northern provinces. The Dutch Republic would have been stillborn, trade and commerce would have remained concentrated in the south, wealth generated by overseas trade would never have flooded into Holland, and the tulip mania could not have taken place.

As it was, Leiden prevailed, but only after a desperate siege that lasted four months. At the end of that time the citizens had run out of food, and in a last bid to save the town, the stadholder ordered the dikes along the Maas to be cut so that the river waters would flood the land around the town and drive out the besiegers. The waters did rise, but not so far as to end the siege. Then in what most pious Dutchmen considered a direct intervention by the Almighty, the wind changed direction, a huge storm arose, heavy rain fell, and the river waters surged forward until the Spanish soldiers were forced to flee. The men of the Beggar fleet were able to relieve the town by sailing their ships over what had been farmland only days before.

The epic resistance of Leiden saved the Dutch Revolt, but the Spanish threat remained a very real one for decades after the first stage of the uprising was successfully concluded. The seven rebel territories formed themselves into a republic—the United Provinces of the Netherlands—with the prince of Orange still in the important role of stadholder and commander in chief. There were several further Spanish invasions of Dutch territory, the last in 1628, and so although the almost incessant conflict was broken by a long truce that ran from 1609 until 1621, the Dutch otherwise faced the expense of maintaining armies in the field and the constant threat of another attack until about 1630. From then until Spain was eventually forced to recognize the United Provinces by the Treaty of Münster, signed in 1648, the threat was all but ended, and the costs of maintaining a substantial army and navy could be cut. The money that was saved was diverted into the Dutch economy, which flourished as never before after 1630.

When Clusius arrived in Leiden decades after the drama of the siege, the university there was the only one in the United Provinces. It was still very new, having been founded only in the spring of 1575. The establishment of such a center of learning was a necessary step for the new nation to take; not only was it expressly intended as a cultural declaration of independence from Spain, but it was needed to produce ministers for the Church and young men fit to govern the United Provinces. At this time most other colleges in Europe gave priority to religious training, and in fact the majority of universities were directly controlled by the Church, which limited the breadth of the education available. But the Dutch government was determined that this should not be the case at Leiden. Teaching was offered in law, medicine, mathematics, history, and other humanist subjects as well as theology, and control of the university was vested in seven curators who were nominated not by the Church but by the provincial parliament and the burgomasters of Leiden.

All this was doubtless much to Clusius’s liking, but the young university’s humanist policy had caused unexpected problems. Between 1575 and the early 1590s, Leiden’s dangerously liberal reputation meant that the leaders of the Reformed Church looked with suspicion on the graduates of its theology school, and Dutch students who planned to pursue a career in the clergy generally chose to enroll at one of the more strictly Protestant north German universities. The ever-present danger that the United Provinces would fall to a renewed Spanish attack deterred scholars from matriculating in other subjects as well, and in its first dozen years Leiden recruited no more than 130 theology students all told and fewer humanists. It took some dramatic Dutch victories and the easing of the military situation in the early 1590s to make the place more attractive to prospective students. The university that Clusius agreed to join, then, although nominally two decades old, was really only just being born when the old botanist finally arrived in the Dutch Republic.

It was a good time to come to Leiden. Suddenly money was available to improve the facilities, hire more staff, buy more books, and offer grants to more young scholars. Over the next half century, the number of students in residence rose fivefold, from one hundred to five hundred, and the library built up one of the most comprehensive collections available anywhere. The university became particularly famous for its school of anatomy, where dissections of human cadavers were carried out. The mysteries of the body were only just beginning to be explored in this period, and anatomy was one of the most fashionable subjects of the day. At Leiden public interest was so great that dissections were frequently carried out before spectators, and visitors were also encouraged to visit the university’s anatomical museum, where over the years wonders such as an Egyptian mummy, stuffed tigers, a giant crocodile, and an immense whale’s penis were put on display. In the fifty years that followed Clusius’s arrival, this sort of excellence resulted in Leiden’s becoming possibly the best—and certainly the most popular—university in Europe. More students were enrolled there than either at Cambridge or at Leipzig, the next two largest establishments in the Protestant North, and Leiden’s student body was also more cosmopolitan and international than any of its rivals’.”

Clusius benefited as much as anyone from this sudden influx of confidence and funds. His principal task was to establish a hortus academicus at Leiden, in imitation of the one set up at the University of Pisa in 1543, which had been the first botanical garden in Europe. Since then similar gardens had been established at the universities of Padua, Bologna, Florence, and Leipzig, but there was still none in the United Provinces. Leiden’s hortus was thus an important symbol not just for the university but for all the Dutch Republic, and the garden was amply funded and laid out on a generous scale. When it was complete, it covered nearly a third of an acre and was divided into four main sections, each of which contained some 350 individual beds.

With the memory of his frustrating years in Vienna still fresh, Clusius was particularly pleased with the rapidity with which his hortus was laid out and planted. He himself was by now too infirm to do any of the physical labor involved, but the university provided him with a very able assistant in the shape of an apothecary from Delft named Dirck Cluyt. Under Cluyt’s direction work on the garden was complete by September 1594, less than a year after Clusius’s arrival at Leiden. It made a pleasant contrast to the dilatoriness of Maximilian and the imperial court.

The speed with which the hortus took shape helped to distract Clusius from some of the difficulties of living in Holland. He had to endure the hard winter of 1593–94, during which Leiden’s mice made short work of 150 of the precious bulbs in his personal collection, and then the miserable weather that the Low Countries experienced in 1594—a year of seemingly constant wind and rain that damaged many of the plants in the botanical garden and did nothing to improve the health of a man who was now sixty-eight years old.

Although he was contractually obliged to look after the garden and to visit it each afternoon in summer to answer the questions of students and distinguished visitors, Clusius’s characteristic intractability led him to refuse his new employer’s request that he deliver lectures on botany as well. Instead, he devoted much of his time to beekeeping and to pottering about the private garden he had insisted that the curators provide for him. While the hortus was largely given over to herbs, medicinal plants, and exotic novelties such as the potato—only recently introduced from the New World and still regarded as quite possibly poisonous—Clusius sowed the collection of tulip bulbs he had brought with him from Frankfurt in his own garden, where he continued to cultivate the flower and delve into its mysteries until his death in 1609, at the very advanced age of eighty-three.

Carolus Clusius was without question the most important botanist of his day. He was a true scientist whose greatest works, such as his surveys of the plants of Austria and Spain, remained the standard texts on their subject for more than a century. He was also a pioneer in the most literal sense—the brief history of fungi that he published in 1601 was more or less the first thing that had ever been written on the subject. For the last quarter century of his life he served as a sort of living vade mecum for the botanists and flower lovers of Europe, keeping up a vast correspondence. This, and his particular interest in bulbous plants, ensured that the tulip spread far more rapidly through Europe than might otherwise have been the case. From this point of view he really was, in the words of another valued compliment—this one from the pen of Prince Emanuel of Portugal—“true monarch of the flowers.”

Yet Clusius’s importance, during his final years at Leiden, lay not so much in the bulbs he brought to the university as in how he studied them once they were planted. The old botanist was not the first person to grow tulips in the United Provinces; according to one reliable chronicler, that honor belonged to an Amsterdam apothecary named Walich Ziwertsz., * a Protestant fanatic who is remembered chiefly for his denunciation of the popular custom of celebrating the festival of St. Nicholas on December 25. Ziwertsz. is known to have cultivated tulips in his garden before 1573, when Clusius was still in Vienna. Nor was the master of the hortus even the first person to raise the flower in Leiden; his own friend Johan van Hoghelande had planted bulbs at the university before his arrival, having received a small stock from Joris Rye. He was, however, the only man in the United Provinces—perhaps in all Europe—who was perfectly qualified to describe and catalog and understand the flower.

Clusius’s first discussion of tulips appeared in his description of Spanish plant life, the Historia of 1576. Over the years he amended and expanded this early work, publishing enlarged treatises on the flower in 1583 and finally in his masterpiece, the Rariorum Plantarum Historia, which appeared in 1601 while he was still at Leiden. It is largely thanks to these works that we know as much as we do about the early history of the tulip in Europe. Clusius’s treatises also included a detailed description of the flowers he had personally encountered or heard of from his many correspondents. In common with all contemporary botanists who took an interest in the genus, he was principally impressed by the ease with which new varieties of tulip could be produced. No other flower, he observed—except perhaps the poppy—was remotely as diverse.

Thanks largely to the efforts of the gardeners of Istanbul, the number of tulip variants known in Europe—each distinguishable by its unique color scheme or the shape and arrangement of its leaves and petals—was already substantial in Clusius’s day. The botanist himself was able to catalog no fewer than thirty-four separate groups, which he classified according to their colors and their shape. He was also the first to distinguish between early-, mid-, and late-flowering tulips, of which the first appear in March and the last not until May.

Working from the solid foundation that Clusius provided, later botanists have added considerably to our understanding of the tulip. The flower has now been grouped with other bulbous plants such as the iris, the crocus, and the hyacinth and is classified among the Liliaceae. In all about 120 different species of tulip—and countless individual varieties—have been cataloged to date.

In scientific works an important dividing line is drawn between what are known as botanical tulips, which originate in the wild, and cultivars, which are hybrids reared in the garden. In Clusius’s time the tulips that were produced in the United Provinces were a mixture of wildflowers and an ever-increasing proportion of cultivars, the earliest of which were produced by chance crossings of two botanical tulips. Botanists have been able to identify fourteen different species of wildflowers as the building blocks that produced the flood of Dutch cultivars that adorned the seventeenth century. Not all played an equal part in creating this diversity. Some botanical tulips produce hybrids more readily than others, and the most malleable species that had found their way to the Dutch Republic included the Persian tulip—today known in Clusius’s honor as T. clusiana—the tapered tulip, T. schrenkii, and the fire tulip, T. praecox. Genes from these species were present in a large proportion of the cultivars that excited admiration in the Netherlands, but in truth Dutch tulips had been produced by crossing flowers that had come to the United Provinces from all points east, from Crete to Kurdistan. That was the secret of the tremendous variety they exhibited.

Whether they were botanical species or cultivars, tulips could be grown from either seed or bulbs. Growing from seed is a chancy business; because plants grown from a single pinch of seed gathered from just one flower can exhibit considerable variation, it is impossible to know exactly what sort of tulip will emerge at the end of this time. Important details such as the color and the pattern of the flower can only be guessed at, which makes the process frustrating for anyone seeking consistency. And it takes six or seven years to produce a flowering bulb from seed, a very time-consuming process that must have seemed even more so in an age when the average life expectancy was not much more than forty years.

Once a tulip grown from seed has matured and flowered, however, it can also reproduce itself by producing outgrowths known as offsets from its bulb. These are effectively clones of the mother bulb and will produce flowers that are identical to it. Offsets can be separated from the mother bulb by hand and, in another year or two, become bulbs capable of flowering themselves. From the point of view of both the commercial grower—who seeks consistency—and the gardener—who prefers not to wait seven years to see a flower—propagation through offsets is infinitely preferable to raising tulips from seed. However, reliance on outgrowths does have one significant disadvantage: Most tulip bulbs will produce only two or three offsets a year and can do so for only a couple of years before the mother bulb becomes exhausted and dies.

For this reason new varieties of tulips multiply only very slowly at first. Once a grower has identified, in a single flower of some new variety, great beauty or strength that he may be able to sell, he will have—even if all goes well—quite possibly only two bulbs the next year, four the year after that, eight in the next year, and sixteen in the fourth year of cultivation. If he parts with some of these bulbs, moreover, he limits his own ability to produce large quantities of the new variety. Plainly, then, it can take a decade for a new tulip to become available in any sort of numbers—and in Golden Age Holland, where propagation was a poorly understood mystery at best, the number of bulbs that were actually produced would have fallen well short of the theoretical maximum. Any rare and coveted variety would thus inevitably remain in short supply for a number of years, and there was nothing that even the most brilliant bulb growers could do to increase production to meet demand.

As soon as tulips of different species are placed close together in gardens, where insects can take pollen from one flower to another, the chance of producing hybrids is substantially increased. And as the new varieties thus created are themselves crossed with other flowers, increasingly elaborate cultivars emerge, bearing the different characteristics of their many forebears. Because tulips of different species do not often grow together naturally, complex hybrids of this sort do not easily occur in the wild. They are, in the strict sense of the word, freaks. But they are also less straightforward, subtler than wildflowers, and thus much sought after by connoisseurs.

The most favored tulips were those that exhibited the most perfect petals and the most eye-catching markings. Indeed, Dutch cultivars of the Golden Age were celebrated and valued far beyond the borders of the republic for the elaborate and often riotous colors they exhibited. By the middle 1630s no fewer than thirteen groups of flowers had been created, each with its own distinctive color scheme. These ranged from the Couleren, which were simple, single-colored tulips in red or yellow or white, to the rare Marquetrinen—late-flowering varieties that exhibited at least four colors. The Couleren would have been botanical tulips, or at least cultivars closely related to them, while Marquetrinen tulips must have been fairly complex hybrids. The latter were grown mostly in Flanders and France and do not figure in the records of the tulip mania.

In the Dutch Republic the most popular of the thirteen groups were the Rosen, the Violetten, and the Bizarden. Rosen varieties, which were by far the most numerous, were colored red or pink on a white ground. During the first third of the seventeenth century, almost four hundred Rosen tulips were created and named. The seventy or so Violetten, as their name suggests, were purple or lilac on white, and the Bizarden, which on the whole were the least favored of the three and existed in only two dozen varieties, were colored red, purple, or brown on yellow. Varieties that reversed the usual color schemes also existed and were generally classed with them; for example, Lacken tulips were purple flowers with a broad white border and were grouped with the Violetten, while the handful of Ducken cultivars, which were red with a yellow border, could be found among the Bizarden.

It was the patterns that these contrasting colors formed that really excited gardeners, and it is impossible to comprehend the tulip mania without understanding just how different tulip cultivars were from every other flower known to horticulturists in the seventeenth century. The colors they exhibited were more intense and more concentrated that those of ordinary plants; mere red became bright scarlet, and dull purple a bewitching shade of almost-black. They were also brilliantly defined, quite unlike the indefinite flushing displayed by other multicolored flowers as their petals shaded gradually from one color to another.

The distinguishing colors of Dutch tulip cultivars—the reds of Rosen tulips and the purples of the Violetten—generally appeared as feathers or flames that ran up the center of each petal and sometimes also formed a border around its edges. These colors occasionally also appeared as mottled patches on the plant’s stem, though they never tainted the purity of the flower’s base, which was always either white (sometimes tinged with blue) or yellow, depending upon the variety. The patterns were unique to each flower, and though two plants of the same variety might closely resemble each other, they were never absolutely identical.

From the earliest days of the bulb craze, Dutch tulipophiles used the subtle variations of these flames and flares of color to grade their flowers according to a strict set of criteria. The most highly prized tulips, termed “superbly fine,” were broken varieties that were almost entirely white or yellow in color, displaying their flames of violet, red, or brown only in thin stripes that ran along the center and the edges of their petals. Flowers that in the opinion of the connoisseurs flaunted their bright colors too wantonly were termed “rude” and were much less cherished.

Botanical tulips are noted for their robust and simple color schemes, so how did the celebrated cultivars of the Dutch Golden Age become so elaborately colored? The solution to this problem is simple but disturbing: They were diseased. The great irony of the tulip mania is that the most popular varieties, the ones that changed hands for hundreds or even thousands of guilders, were actually infected with a virus, one apparently unique to tulips. It was this virus that caused both the spectacular intensity and the variations in the colors of their petals and that explained why tulips, alone among the flowers of the garden, displayed the distinct, intense, and brilliant colors that collectors came to crave.

Even in Clusius’s day it was obvious that something strange was happening to the tulips grown in Leiden and elsewhere. A bulb that one year had produced a unicolored tulip might become a Rosen or a Bizarden the next. This process was known as “breaking,” and the bulb of a flower that had undergone the process was said to be “broken” while those that remained unicolored were called “breeders.” The whole process was extremely unpredictable. There was no way of telling if or when a flower would break; one tulip might bloom in the spring with a dazzling new array of colors, while another, of the same variety and planted next to the first in the same flower bed, remained quite unaffected. Breaking was common in some years, less so in others. Similarly, a broken bulb might—albeit rarely—produce an offset that turned out to be a breeder, and no grower could be sure that a breeder bulb would not break. The only certainties seemed to be that tulips grown from seed were invariably breeders and that, once broken, a mother bulb would never again produce a unicolored flower.

There were clues here to the nature of the disease, and Clusius was a careful enough observer to notice that broken tulips were slightly smaller and definitely weaker than the flowers produced by breeder bulbs. But at a time when the mechanisms by which diseases are communicated remained unguessed at, the phenomenon of breaking seemed akin to magic to most of his contemporaries. Try as they might, growers could not force a breeder bulb to break when they wanted it to. Some turned to alchemical potions made of pigeon dung, which they applied to the bulbs; others tried cutting the bulbs of two different-colored tulips in two and binding the opposing halves together in the hope of producing a flower sporting both colors. These devices rarely had the desired effect.

Exactly when the tulip became infected with a virus is not certain. The earliest observations of the phenomenon date to about 1580, but the disease was probably older than that. In truth the plant became vulnerable to disease as soon as it entered a garden; any flowers raised in artificial proximity by humans face threats they do not encounter in the wild. Cultivars may be poorly cared for or discarded in favor of some new favorite, but in particular they can pick up diseases to which the more robust botanical species have developed an immunity or that at least spread more slowly in the wild.

The mystery of breaking remained unsolved until well into the twentieth century, when the agent that causes the disease, sometimes called the mosaic virus, was finally identified by staff at the John Innes Horticultural Institution in London. By permitting aphids to feed on broken bulbs and then on breeders, they were able to show that the breeder bulbs visited by the aphids broke twice as often as a control sample—thus simultaneously proving that the disease was caused by a virus and demonstrating the mechanism whereby it was transmitted from one tulip to another. Further experimentation showed that the mosaic virus could infect both a flower when it was growing in a garden and a bulb that was being stored prior to planting. Perhaps ironically, given the efforts of old Dutch growers to induce breaking by binding half-bulbs together, the method used at the John Innes Institute to persuade aphids to feed alternately on infected and uninfected tulips was to graft halves of broken bulbs onto breeders.

Well before Clusius’s death, the broken tulips he grew in his private garden at Leiden were attracting the attention of connoisseurs eager to secure specimens of these unique new flowers for their own gardens. The old botanist soon found himself almost overwhelmed with requests for tulip bulbs. Many, he knew, came from people who merely wanted to follow the fashion for the flower and had no real interest in botany and no idea how to cultivate bulbs; others were from people he suspected of planning to sell his bulbs for whatever they could get. In any case, his own supplies were not remotely adequate to meet the demand. “So many ask for them,” he wrote to his friend Justus Lipsius, a humanist scholar who had been one of the pillars of Leiden University in its formative years, “that if I were to satisfy every demand, I would be completely robbed of my treasures, and others would be rich.”

Unfortunately for Clusius, some at least of those who implored him for bulbs would not take no for an answer. Just as he had been in Vienna, he began to be plagued by repeated thefts from his garden. Twice during the summer of 1596 and again in the spring of 1598, thieves stole tulip bulbs from him while he was away. The total loss must have been substantial, because we know from Clusius’s surviving letters that more than a hundred bulbs were taken in just one of these raids. The old man was so distressed by the loss—and by the familiar disinterest that the authorities at Leiden showed in investigating the thefts—that he vowed to give up gardening altogether and disperse the rest of his collection among his friends.

Over the years Clusius’s reputation has suffered from the suggestion made by one contemporary chronicler that these thefts occurred because he asked an exorbitant price for his flowers and stubbornly refused to hand over bulbs to anyone who would not meet it. Nothing could be further from the truth. Throughout his long career the botanist showed great generosity in sending samples of his finds to friends for nothing—“con amore,” as he sometimes put it in his letters—and the only people he refused to supply were those he suspected would not value his gifts. The people who organized the theft of his bulbs at Leiden fell into the latter category, and Clusius was surely right to suspect their motives from the start.

Nevertheless, the thefts did have one positive result. Clusius’s tulips were far from the only ones in the United Provinces in the 1590s, but his collection was certainly the most varied and the best. As a result of the thefts these precious bulbs were distributed throughout the Netherlands, north and south, and they flourished. In some of their new homes, at least, they must have become parents of new hybrids, varieties that in their turn bred and formed an important part of the stock of bulbs traded in the next century. The Leiden bulbs thus became the progenitors of the flowers traded later in the century, and thanks in part to them, in the words of a chronicler, “the seventeen provinces were amply stocked.”

*Surnames were still relatively uncommon in the United Provinces in the sixteenth and early seventeenth centuries. Most people still identified themselves using patronymics—Walich Ziwertsz. would have been the son of one Ziwert or Sievert. Because it was unwieldy to spell out the full patronymic, which in this case would be Ziwertszoon (“Ziwert’s son”), it was also common practice to abbreviate written names by placing a period after the z of “son.” When spoken, the name would have been pronounced in full.

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