Was Girolamo Cardano an inspiration for Shakespeare’s character of Prospero?

Girolamo Cardano (Pavia, 1501 – Rome, 1576?) also known as Hieronymus Cardanus and Jerome Cardan was a typical man of the Italian Renaissance: a genius, a polymath as well as an eccentric who had a difficult childhood. His father was Fazio Cardano (1445 – 1524) a friend of Leonardo da Vinci and author of the first printed edition of the  Perspectiva Communis by John Peckam (1230 – 1292).

Girolamo Cardano was born unwanted and out of wedlock, but thanks to his strong will he was able to reach the peak in the scientific and philosophical world of his times. He became a physician in 1526, practicing at Saccolongo, near Padua and then in Gallarate. In Milano he was excluded from the medical profession due to his illegitimate birth. He wrote several books, which were read with great interest throughout Europe. To mention just a few:  Liber de Ludo Aleae in which we find the first law of statistics, the Ars Magna the first advancement in the field of algebra from the times of the Greeks, where we can find the solution to equations of the third and fourth degree. Then the De subtilitate the first prototype of pocket encyclopedia, where he had probably access to Leonardo Da Vinci’s notebooks through Leonardo’s disciple Ludovico Melzi. A the end of his life he wrote the De propria vita a sort of autobiography which is still in print in most countries of the world, even in China, really a classic of this genre, often cited along those of Benvenuto Cellini and Michel de Montaigne. We could proceed with the list of his works for several pages. They were mostly dealing with medicine, astrology, history and philosophy. His Opera Omnia in ten thick volumes (but not really containing all his works) was printed in Lyon in the year 1663 and a reprint of this monumental work was carried out in Chicago, in the year 1972. Cardano was an admirer of Paracelsus and Agrippa and a strong critic of Aristotle. Among his many merits we may also add the fact that he did not believe in witchcraft and detested war. In another of his famous books, the De Rerum Varietate he tells us the story of a woman at the time of his father who was convinced she was possessed by the devil and because of this she came close to being burnt at the stake, but Cardano’s father had a magic cure. He suggested bread and eggs to be fed to that wretched lady and after a few days she regained her wits!

Portrait of Cardano from a XVII century French book
Portrait of Cardano from a XVII century French book

Girolamo Cardano was an open-minded man and was in correspondence even with Protestants. He had his share of envy to bear because of his professional achievements. He was accused of heresy and arrested on October 6th, 1570. The books on which the inquisitors set their sharp eyes were first the De Rerum Varietate and then the Duodecim Geniturarum in which he had cast the horoscope of Jesus Christ, among other famous persons. Finally he agreed to recant his opinions, burned his unpublished manuscripts and was treated with leniency. He had been lucky because he had powerful friends ready to help him; one of these was John Hamilton (1511 – 1571), the archbishop of Edinburgh.

Here is how they met. It was the year 1552 and Cardano was living in Milan, his hometown, very busy with his studies. One day he received a letter from Hamilton asking him to meet him at Lyon, France. The Scotsman was very sick with chronic asthma and had heard that Cardano had a cure. After some hesitation, Cardano traveled to France and waited in Lyon for several days for the arrival of the Archbishop. Then another letter reached him, asking him to carry on with his trip and go to Scotland. Hamilton could not leave because he had important business to attend. Cardano travelled to Paris and then to London, where he arrived on June 29th, 1552 and from there he went up to Scotland.

John Hamilton was the Archbishop of St. Andrews and Lord Treasurer, the bastard son of James Hamilton, 1st Earl of Arran. Cardano’s cure for asthma worked wonders on the Prelate, but he had to stay with him for 76 days. When he left, Hamilton had fully recovered his health and survived until 1571 when, after having taken the side of Mary Queen of Scots and baptized the infant James, later King James VI, ended up being hanged at Stirling Castle.


On his way back he stops in London where he has a private audience with King Edward VI (1537–1553) affected by tuberculosis. He is escorted by his friend John Cheke (1514–1557) a Hellenist and tutor of the king. He casts a highly inaccurate horoscope of the fifteen-year-old king of England. It was a dangerous question from which he managed to free himself with a generic good forecast. The sickly king died just a few months later. This shows that Cardano’s fame as an astrologer was greater than his fame as a physician. The impression he made on the English Court was deep and long lasting and for this reason he has been the subject of several English books since then. We can find several biographies written on him during the last century by English authors. The latest is by Allan Wykes written just a few years ago. In Italy Cardano is not as well known, as he should be. Only his autobiography is reprinted from time to time. Recently his bizarre Apology of Nero was translated into Italian and published by Valdonega, in Verona, following a suggestion by the author of these notes and printed with a splendid introduction by Giovanni Arpino. I say bizarre because for the first time the maligned Roman emperor is seen as victim of events greater than himself not as a sort of Hollywood monster.

The behavior of Cardano, at times, could look strange too. He openly admitted that a ghost, inherited from his father, was always at his side and that he heard demons stirring and speaking behind his back, with a strong smell of sulpur in the air.

William Shakespeare
William Shakespeare

Having shown that Cardano’s influence was indeed great in England and Scotland, we can now add a few notes about William Shakespeare. We believe that the author of the comedies and poems is really that Shakespeare who was born and buried in Stratford-upon-Avon. He likely met people who knew Cardano. The bard of Stratford was born in 1564 and moved to London in 1592, forty years after Cardano’s meteoric passage through the city, but Cardano’s popularity was still great. Shakespeare may well have known about the misery of that great man, prisoner of the Inquisition in Rome and of his obscure death. For instance the famous soliloquy that begins with To be or not to be is taken from Cardano’s Comforte a translation in english of his De Consolatione which was published in 1576 and went two more editions in the following years.

I was struck by the similarities between Cardano and the figure of Prospero in the The Tempest of Shakespeare, unnoticed by all Shakespeareans critics. In fact Cardano and Prospero have many things in common. Both of them have a ghost at their command; both are noblemen from Milan; both are magicians; both were thrown in jail and exiled; both are book-loving scholars who had renounced their magic; both were ruined by people they had trusted.

Prospero threatening Caliban
Prospero threatening Caliban


Knowing I lov’ed my books, he furnished me/From mine owne Library, with volumes, that I prize above my Dukedome

The character of Prospero is very much alive, not fantastic and for this reason some critics have been led to think that he was a sort of alter ego of William Shakespeare. One last note: one of Shakespeare’s plays has been lost. Its title was Cardenio. All the critics seem to agree that this name may be connected with a story from the Don Quixote of Cervantes, but the similarity with the name Cardano is, nonetheless, fascinating.

‘As you from crimes would pardon’d be, let your indulgence set me free.’

First printed in September 1987 on The Golden Argosy, Stayton, Oregon, USA


2 commenti su “Was Girolamo Cardano an inspiration for Shakespeare’s character of Prospero?”

  1. Dear Angelo, once again you struck me with a revelation that only a man of culture can disclose.
    I knew Cardano by reading your “Nero”. Now I discover this unknown fact that deserves an ad hoc essay. My congrats.


Lascia un commento

Questo sito usa Akismet per ridurre lo spam. Scopri come i tuoi dati vengono elaborati.