Alchemy in the Renaissance: The Mysterious Isabella Cortese

This text is also available as a YouTube Video.

How do you become an alchemist? This is what a 16th-century book suggests:

1. Never work with any ‘Grand Masters’
2. Use sturdy and well-crafted equipment made of terracotta or glass
3. Make sure to keep your work secret
4. Regulate the fire often and carefully
5. Always have your tools at hand, especially tongs
6. Deny your expertise in alchemy should anyone ask about it and do not allow anyone into your workshop
7. Learn about the materials used in these operations, especially metals such as gold and silver
8. Do not teach the Art to anyone, ‘because revealing the secret of something causes it to lose its efficacy’
9. Find a trusted and faithful servant, yet never leave them alone in your workshop
10. When you succeed in your experiment, thank God and give charitably to the poor.

This advice is said to come from a woman; it’s from The Secrets of the Lady Isabella Cortese, published in Venice in 1561. But what does this book, and the mysterious writer to whom it is attributed, tell us about women, science, alchemy, authorship, authority and expertise in the Renaissance? Let’s talk about the elusive Isabella Cortese, and what her role as a ‘professor of secrets’ can tell us about gender and knowledge in the Renaissance.

Part 1 – Who was Isabella Cortese?

Well… The short answer is, we don’t really know. BUT that’s ok. The fact that we can’t be sure is itself interesting, I promise, and tells us a lot about what was happening in this period. Let me explain. In 1585, a Dominican friar called Tommaso Garzoni (1549-1589) wrote a book listing over 500 professions; ‘all the professions of the world’, the Piazza universale di tutte le professioni del mondo. You could find all the usual occupations, of course: tailors, cooks, craftsmen… But there was also something new: ‘professors of secrets’. Garzoni described them as people who sought out things ‘whose reasons are not so clear that they might be known by everyone, but by their very nature are manifested only to a very few; nevertheless they contain certain seeds of discovery, which facilitate finding out the way toward discovering whatever the intellect may desire to know’. 

So… these professors of secrets were people interested in the wonders and secrets of nature – the occult, hidden virtues and properties of natural things, and how to manipulate them, often using alchemy, to make things like remedies and cosmetics. But you might be thinking, why professors? Well, because they were ‘professing’ these secrets, teaching them, especially in printed books of secrets, which contained many of these recipes and which were a best-selling genre in 16th-century Italy and beyond. They were on the margins of academic culture and the learned world. So, who were these people? Well, Garzoni listed many of them, including the best-selling Alessio Piemontese and Leonardo Fioravanti (and if you’re interested in this fabulous Bolognese surgeon who was often accused of being a charlatan, I suggest you check out my video on him). Anyway, among the list of men, one single female name stands out: Isabella Cortese, a ‘professoressa’ of secrets, who was the only woman in the list.

Now, women practising alchemy was not unusual, especially those from wealthy families, nor was it unusual for them to create manuscript collections of this kind of recipe. I made a video about Caterina Sforza a while back, and she’s perhaps the best example of a female ‘secretista’ – go check out that video if you’re intrigued. I just wanted to highlight the close relationship between Caterina and her assistant, Luigi Ciochi, a ‘loyal and discreet servant’ and how similar that is to Isabella’s description I started this text with. But anyway. What was unusual though was for these collections to be available in print. And Cortese’s book was a big hit – there were 7 editions between its first publication in 1561 and 1599, and the collection was translated into German, and reprinted twice. But who was she? Well, unfortunately, very little is known about her.  In fact, the main source we have is her own book, in which she describes herself as a noblewoman, possibly from Venice, who had travelled extensively throughout Central and Eastern Europe, looking to learn all about alchemy and perfumes, which are the main subjects of her recipes. She dedicated the book, her only known work, to her brother, the archdeacon of Ragusa, Mario Chaboda (1505-1582). Contrary to her, even though he was just as interested in alchemy, he hadn’t been successful in his pursuit of the ‘Great Art’. Enter Isabella Cortese, ready to teach her brother – and her readers – all about it.

Now, historians have been debating her identity for centuries. Who was the person behind the name? Did Isabella exist, or was she a pseudonym? And if so, was it really a woman behind the name? I don’t want to bore you too much with this debate, so here’s a summary. The first possibility is that there really existed someone called Isabella Cortese. One historian described her as ‘a learned and successful woman of an uncertain fate’. This is such a tempting hypothesis, I understand why we would want it to be true. There was indeed a Cortese family in Modena, and another in Rome, and its descendants migrated, like the poet Giulio Cesare Cortese (1575), born in Naples. However, I couldn’t find any records of a woman called Isabella in the archives that matched the period in which the book was published. One possible clue is a document called a ‘privilegio a stampa’ found in Venice, which is essentially when someone asks to be the only one allowed to print a specific book. In this case, a publisher and bookseller called Curtio Traiano was granted the privilege to be the only one to print both Timotheo Rossello’s and Isabella Cortese’s book. And he was brother-in-law to Giovanni Bariletto, who ended up publishing both books. Some historians say that, if there’s one thing we can trust, is the Venetian bureaucracy, and so its officials would have investigated this case thoroughly, which would indicate that Cortese was a real person. I’m personally not persuaded by this argument.

Another possibility, which 18th and 19th-century historians already believed in, was that she was a pseudonym created by the publisher. But why would they choose a female name? This, to me, is more interesting than the question of her identity. Let me give you some context. There are many similarities between Isabella’s book and those of her contemporaries, such as Alessio Piemontese, but especially Timotheo Rossello – and both of these authors were very likely pseudonyms too, possibly created by a man called Girolamo Ruscelli, a poligrafo, or a ‘tradesman of the pen’ – so, a professional writer and editor. All these books contained the same kind of recipes, and Ruscelli even published another volume under his own name in 1567. ‘Borrowing’ from other books was extremely common in a period in which copyright law was virtually non-existent, and publishing under pseudonyms was commonplace, too. Just to give you an idea, both Cortese’s and Rossello’s books were published in the same year, 1561, by the same publisher in Venice, Giovanni Bariletto. They were also both dedicated to the same person, Mario Chaboda, the archdeacon of Ragusa, which had once been under the control of Venice. Chaboda was an avid if perhaps frustrated alchemist; he taught at the University of Padua, a centre of international academic exchange, and he was a member of the Accademia dei Confusi in Viterbo – by the way, that’s where Ruscelli was from. What if Chaboda had met Ruscelli through these connections?  To make things more complicated, remember that Cortese writes that Chaboda was her brother; and his Slavic name was Kordiza – which does sound similar to Cortese. What if he was the one behind the recipes, perhaps along with Ruscelli?

Later, when Ruscelli published his own book, it started with the same recipe as Cortese’s book. It’s also intriguing that, just as quickly as they appeared on the market, the names of both Rossello and Cortese disappeared; nothing more is heard of them. Alessio Piemontese, on the other hand, became the ultimate best-selling book of this kind, and many people believe that Ruscelli was the person behind this character, too. He even said this in his own book, that he had created Alessio Piemontese. So, maybe Ruscelli, probably collaborating with other people, such as publishers, created three different authors for three different collections of recipes and, seeing which one of them did better in the market, dropped the other two. Another clue here is the same 16th-century text about professors of secrets I quoted earlier, in which Garzoni listed:

Excessively harsh on Agrippa perhaps, but anyway. Garzoni believed Cortese and Piemontese to be editorial inventions, and I tend to agree. Unfortunately, all we can do is give it our best-educated guess; who knows, maybe one day we’ll find a new document hidden somewhere in the archives and know more. Still, intriguing as this investigation is, at least to me, it’s not what I find most interesting about Isabella Cortese. Let’s talk about the book itself and why it would have been attributed to a woman in the first place. What does that mean in terms of the relationship between women and knowledge in the Renaissance?

Part 2 – Women and the Ethics of Knowledge

So, if we accept the premise that Isabella Cortese was an editorial name, that begs the question: why choose a female name as the author of a recipe book on alchemy? Just think of all the female writers of the past who have done the opposite: George Eliot, Isak Dinesen, George Sand were all male pseudonyms for women… Or the Bronte sisters, who chose gender-neutral names: Acton, Currer and Ellis Bell.

Let’s think of the name itself. Cortese is an anagram for secreto, as many historians have pointed out, and maybe there’s something to it, even though it feels very Nicholas Cage in that irresistibly silly film, National Treasure. But Cortese also literally translates as ‘courtly’; it makes you think of an aristocratic, courtly lady, and this was a time in which alchemists were in high demand in Italian courts, and many members of the nobility – men and women – had their own laboratories. It calls to mind Caterina Sforza, and by this association, the book gains in authenticity, but also authority. Still thinking of the name, Isabella is also evocative of Isabella d’Este, the famous patron of the arts but also, a well-known alchemist and secretista herself, famous for her unique perfumes. Secretive attitudes were still closely associated with alchemy, and these female alchemists. So, a book promising to reveal the secrets of a great lady, whose name evocated all these associations, a text aimed at women, would be a clever choice; it would make commercial sense.

The publication of this book under Cortese’s name indicates that 16th-century publishers recognised there would be an interest among their readers in a book written by a woman, in which she shared her knowledge and experience in alchemical matters. And, although the book could be useful to both men and women, it was marketed to women; it was meant for ‘every great Lady’. Although many women alchemists, like Caterina Sforza and Isabella d’Este, compiled manuscript collections of recipes, none of them were available in print. One of the things that made their recipes so valuable was the fact that they were secret, and unavailable to most people. But this was quickly changing. There was an increased move away from secrecy and towards sharing knowledge, in no small measure thanks to the impact of the printing press. Alessio Piemontese had become famous in part because he had declared that knowledge should be shared openly. In his book, he had written how he had always guarded his secret recipes jealously. Once, he had even declined to share a recipe with a physician, whose patient had subsequently died. This provoked an epiphany in the author, or so the story goes. 

Cortese tells us little in her book about her own life, but there’s a similar story. When she was living abroad, she met a priest on his way to Krakow, who was carrying secret letters to a Polish humanist and scholar. Unfortunately for him but fortunately for Isabella, the priest fell ill and died on the way. Cortese found that these letters were full of precious alchemical secrets, which she included in her book, attributing them to Father Benedetto of Vienna. This story evokes some alchemical themes, such as learning secret knowledge from a master and the idea of revelation, but, just as in Piemontese’s case, Cortese chooses openness over secrecy; she publishes the content of these secret letters in her book. Of course, in both cases, these are probably made-up stories, but they illustrate this move towards openness and accessibility where alchemical knowledge is concerned. Moreover, there’s a shift from an allegorical and hermetic writing style to a practical, matter-of-fact, technical way of teaching readers.

The ethics behind accessibility to knowledge and openness were being debated by humanists, who were discussing basically who should be allowed to know what. This made sense at a time in which books were increasingly being published in the vernacular languages rather than Latin, and literacy was spreading quickly; so, more people would have access to this kind of knowledge than ever before. Someone like Girolamo Ruscelli, who was a professional writer and editor, would know the tastes of his reading public, especially if he was indeed the person behind the Secrets of Alessio Piemontese, just a few years earlier. So maybe a professoressa of secrets was invented to fill a void in the market and to move away from the secrecy exemplified by Caterina Sforza and Isabella d’Este. 

But there’s more to it than that. There are some fundamental differences between the other recipe books of the time and Cortese’s. Timotheo Rossello’s secrets, which are dedicated to ‘men and women of great intelligence’, are respectful, not to say reverential of the past and ancient authorities, especially the great alchemists. Rossello’s book is full of explanations and descriptions; Cortese’s is much more direct. Rossello’s directions are vaguer and more abstract; Cortese’s are precise. Isabella Cortese, as I said at the beginning of this text, urges her readers to drop the study of these great masters completely. Her work is a break with tradition in more ways than one. For her, practical experience shouldn’t just complement book learning; it should replace it altogether. Maybe using a female name for this book would allow for such a rupture more than a man’s – without losing authority. In fact, authority is created by doing just that. So, what if this was another reason why a female name was chosen for the book? 

Part 3 – Gender, Experience, and Authority

Let’s go back to Cortese’s advice on how to become an alchemist. This is what she wrote:

Cortese is openly contemptuous of the great masters and alchemical theory; she advises against reading to learn alchemy and the secrets of nature. Now, she wasn’t the only one to believe that at the time, but there was a gender aspect to this. For instance, travelling and learning from practical experience, from all kinds of people, was increasingly lauded as superior to the study done at universities – at least by those writing popular books. This is what Alessio Piemontese wrote:

Now listen to what Leonardo Fioravanti, another professor of secrets, wrote:

Both Piemontese and Fioravanti considered women valid sources of knowledge – even if they are slightly condescending in how they describe them. They are referring here, of course, not to women like Isabella Cortese or Caterina Sforza, but rather to illiterate herb women, midwives, and matrons living in the countryside. Contrary to Cortese, they hadn’t studied all the authorities before rejecting them, nor travelled far and wide; they didn’t have access to that. But they had amassed knowledge through their roles in their families and communities.

Fioravanti was a surgeon as well as an experimenter and he wrote how sometimes physicians would be baffled by a case:

So, even ‘simple’ country women, because their knowledge came primarily from experience rather than theory, could have the upper hand. In many of these popular recipe books, women are credited with miraculous formulas – even if they’re not usually named. So, in the debate about authority and expertise, the knowledge women had acquired through practice was often used to make the point that direct experience had value. And, if women tended to be associated with praxis, men were associated with theory. Of course, this is a false binary and an oversimplification; Cortese herself tells us she spent decades studying alchemical books. But recipe books were at the core of a discussion about knowledge and its value. These books tended to prioritise practice over study, and trial-and-error over book learning, often relying on women to make this point. Isabella Cortese’s book is the best example of just that. And, because these books are focused on practical applications of alchemy rather than its abstract mysticism, it’s possible that publishing a book under a female name would highlight this trend. Later, with the spread of Paracelsianism, this pragmatic alchemy would gain even more traction. 

And, if on one end of the social spectrum you’d find ‘a poor country woman’, at the other end, there were highly learned women like Caterina Sforza, with their formulas for the philosopher’s stone. But some less extraordinary women were also interested in learning about these subjects, too. Knowledge about medical and cosmetic recipes, which often relied on alchemical methods, was spreading in this period among women, especially in cities like Venice. Perhaps a recipe book attributed to a woman would be able to encapsulate both the experience learned from practice women had, from taking care of their neighbours when they were giving birth and making soap at home, as well as the more aristocratic and refined pursuits of female alchemists of the Renaissance. Maybe a book like Cortese’s could encapsulate female knowledge at both ends of the spectrum and capitalise on what readers, especially female readers, might want to learn from a female secretista. It’s likely that the publisher thought that the author’s name would increase sales, combining this female authority and expertise gained through experience and highlighting to women that this was a book meant specifically for them. So, if you’re still with me, you might be wondering – what was inside this book, anyway?

Part 4 – The Secrets of Isabella Cortese

Her collection was composed of four parts, or ‘books’. The first and shortest (only 30 recipes) dealt with medicine (so, things like remedies for the plague and syphilis, antidotes to poisons, and formulas for recovering after childbirth), and many of these recipes relied on alchemical operations such as distillation, multiplication, and transmutation. The second part (composed of 70 recipes) was alchemy in a strict sense – recipes for elixirs, the philosopher’s stone, and how to make gold. This is the section that had come from the priest I mentioned earlier, according to Cortese, but the instructions are clear and accessible. The third book (with 99 recipes) focuses on marvellous or wonderful secrets, which tend to involve a transformation of some sort (things like how to make mirrors or create gold ink for illuminating manuscripts, but also more mundane concerns such as removing stains from fabrics and even curing male impotence.) As always, please don’t try this at home, but this is what the recipe looks like:

To straighten out the [male] member: Testicles of quail, oil from the inner bark of storax and from the elder tree, large-winged ants, musk and amber from the Oriennt-just mix these together and apply as needed.

Doesn’t that sound delightful? Anyway, the last and longest part of the book (with 221 recipes) is concerned with cosmetic recipes, such as skin lighteners, colours for the face, perfumes, and depilatory formulas. Again, these recipes also rely on alchemical operations and ingredients such as alum and silver.

Now, didactic as these recipes may be, and having been created through trial-and-error, paradoxically and perhaps ironically, no further experimentation is encouraged. As Cortese wrote to her brother, he should ‘follow what she says’. The recipes were already ‘perfect’, and needed no improvement. Of course, this doesn’t mean people didn’t experiment, made changes, or improved the recipes to suit their goals. Just think of how we all make changes when making a recipe from a cookbook: you might have budgetary constraints, not have an ingredient or a specific tool, be allergic to something, or maybe if you’re like me, you don’t see the appeal in icing biscuits and prefer them plain. That all happened to people following Cortese’s recipes, too. And we know that because people left annotations in the margins of these books. They also created their own manuscript recipe books, copying recipes from various sources, including printed books. This is the case of this manuscript collection, which I found at the Wellcome Library (MS. 215). In this notebook, recipes from both Cortese’s and Rossello’s books were copied, and sometimes they’re attributed to the wrong person – again highlighting the confusion over authorship and recipes. But it’s possible that the main reason why readers weren’t encouraged to experiment themselves and to follow recipes to the letter had to do with preserving authority and expertise. Isabella Cortese writes that, if you don’t obtain the desire result from a recipe, then you have made a mistake, you haven’t followed it properly. 

If you followed the recipes correctly, you would gain access to a world of practical knowledge and taught by the woman who had herself gathered this collection of recipes. It’s very likely that there’s much fiction behind this little book. But it’s precisely because Isabella Cortese was likely an editorial invention that her book offers us such a rich glimpse into the world of early modern alchemy. If, at a first glance, it may seem that Cortese is telling readers to reject alchemical authorities, a closer look shows us that she is actually replacing one kind of authority with another: theory, associated with men, should make room for practice, associated with women. This ‘new alchemy’ illustrated by Cortese was open to everyone, including and especially women. This was an everyday pursuit; women were invited to engage in alchemy as Cortese’s apprentices, using their kitchens as their laboratories. They could make toothpaste, dye their hair, get rid of stains on their clothes, perfume and heal their bodies, taking care of themselves, their families, and their homes. This is a typical recipe:

Not only were these recipes of interest to women, but they would be familiar with the structure of recipes and how they organised information. They would know how to follow recipes without measurements or detailed instructions, using their own experience and knowledge to complement the missing elements of the recipe.

These recipes were similar to those in other contemporary books, like Alessio Piemontese’s, although they were more alchemical in general. They were also similar to the experiments of alchemists such as Caterina Sforza. So, in a way, Cortese’s book appears as a sort of patchwork of different traditions, appropriating different identities and associations to create an editorial success, all while making the case for a ‘new alchemy’ in which women, both ‘simple’ illiterate women from the countryside and highly educated women, had mastered this knowledge through direct and practical experience. This was not ‘high’ alchemy, with its esotericism and arcana, it was technical alchemy, used to improve everyday life. It’s no wonder, perhaps, that this book would be connected to women – both in terms of who it was attributed to and who its intended readership was. And, in the centuries following the publication of this book, many others focused on medicine, cosmetics and perfumes were attributed to ‘great ladies’ like Cortese, such as The Queen’s Closet Opened. Cortese’s book legitimised women’s knowledge, and the fact that it was available in print made it widely influential.

And, just look at this – this is a graphic novel that I found in Italy years ago, inspired by Isabella Cortese. It’s called Bianco come un fiore di gelsomino, or white as a jasmine, and it tells the story of Isabella having to deal with an increase in ecclesiastical control over alchemy in Rome. Apparently, it’s used to teach the history of alchemy in schools, how cool is that?! 

Final Thoughts

The people writing and publishing books of secrets clearly recognised a gendered element to expertise and authority in knowledge about alchemy, medicine, cosmetics, and natural philosophy. There was an association between women and a kind of knowledge derived from practical experience, and there was also a growing expectation that knowledge should be shared openly, not hoarded and kept secret. Just contrast Alessio Piemontese’s story, in which he let a person die because he didn’t want to share a secret recipe for a remedy, with the many women that appear in anecdotes in these books coming to the rescue of patients and treating them when physicians didn’t know what to do, generously sharing their expertise. The publication of this book also indicates the existence of a female readership interested in learning about these recipes. 

The Secrets of Isabella Cortese is such a fascinating book to think about gender and knowledge in the Renaissance because regardless of there being a ‘real’ Isabella, women are present in both parts of the equation; they are the producers or makers of knowledge, the ‘authors’ as it were, as well as the ones receiving and learning this knowledge too, the ‘readers’. Plus, much of this knowledge is focused on what was considered the feminine sphere – the home – but also, on the female body itself. Recipe books were a European phenomenon, and most of them were written or attributed to men, and men were a big part of their readership. They were central in Renaissance culture, medicine, and alchemy, and used as examples in the debates about ethics, knowledge, authority and expertise. Of course, Cortese’s book is an outlier. It follows trends (after all, publishers were interested in selling as many books as possible), but it also creates them. A well-travelled woman who decides to share her alchemical knowledge openly, especially with women, is indeed something new.  

Women are often left out of history. But in books of secrets, women can be found in dedications, titles, introductions, anecdotes, and recipe headings, with Cortese being, of course, the most well-known example. This illustrates how women were a part of the vibrant world of early modern science, alchemy, and medicine. As for Isabella herself, who knows. Maybe other books attributed to a male author were written by women; maybe this book was written by one or more men. The question of authorship – and I do love a good investigation like this – turns out to be less interesting than what the book can tell us about gendered attitudes to knowledge and its value. The name Isabella Cortese may well be an invention, but the deliberate use of a female name associated with courts and experimentation was significant as it boosted the book’s authority and appeal. The same can be said about the expectation of a female readership and the focus on a domestic, practical alchemy. This book was widely popular and probably read by many women. It reminds us that women were a big part of the world of science, medicine, and alchemy in the Renaissance, even if they’re often left out of how history is told. 

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References:

Isabella Cortese, I Secreti della Signora Isabella Cortese (Venice: 1565).

Leonardo Fioravanti, Capricci Medicinali (1561).

Tommaso Garzoni, Piazza universali di tutte le professioni del mondo (1587).

Alessio Piemontese, I Secreti di Donno Alessio Piemontese (1557).

Timotheo Rossello, Summa dei secreti universali (1561).

Girolamo Ruscelli, Secreti nuovi (1567).

Further Reading:

Rudolph Bell, How to Do It: Guides to Good Living for Renaissance Italians (1999).

William Eamon, ‘Arcana Disclosed: The Advent of Printing, the Books of Secrets Tradition and the Development of Experimental Science in the Sixteenth Century’, The British Journal for the Philosophy of Science 35(1) 1984, pp. 111-150.

William Eamon, Science and the Secrets of Nature: Books of Secrets in Medieval and Early Modern Culture (Princeton: Princeton University Press, 1994).

F.-S. Feuillet de Conches and A. Baschet, Les femmes blondes selon les peintres de l’École de Venise (1865).

Elaine Leong and Alisha Rankin (eds.), Secrets and Knowledge in Medecine and Science 1500-1800 (2011).

Claire Lesage, ‘La litterature des “secrets” et i Secreti d’Isabella Cortese’, Chroniques Italiennes, Université de Paris III, 36, 4/1993.

Julia Martins, ‘Follow what I say’: Isabella Cortese and Early Modern Female Alchemists, Living History (2022).

Julia Martins, Kitchen Alchemy in the 16th Century, Brewminate, 2017.

Julia Martins, ‘Secrets of Women’: Translating the Female Body in Early Modern Books of Secrets (1555-1700), PhD Thesis, King’s College London (2023).

Meredith Ray, Daughters of Alchemy: Women and Scientific Culture in Early Modern Italy (Cambridge MA: Harvard University Press, 2010).

Massimo Rizzardini, Lo strano caso della Signora Isabella Cortese, professoressa di secreti, Philosophia II 2010(1), pp. 45-84.

Anna Santoro (ed.), I secreti della Sig. Isabella Cortese (1999).