Girolamo or Hieronimo Cardano‘s name was Hieronymus Cardanus in Latin and he is sometimes known by the English version of his name Jerome Cardan.
Girolamo Cardano was the illegitimate child of Fazio Cardano and Chiara Micheria. His father was a lawyer in Milan but his expertise in mathematics was such that he was consulted by Leonardo da Vinci on questions of geometry.
In addition to his law practice, Fazio lectured on geometry, both at the University of Pavia and, for a longer spell, at the Piatti foundation in Milan.
When he was in his fifties, Fazio met Chiara Micheria, who was a young widow in her thirties, struggling to raise three children.
Chiara became pregnant but, before she was due to give birth, the plague hit Milan and she was persuaded to leave the city for the relative safety of nearby Pavia to stay with wealthy friends of Fazio.
Thus Cardan was born in Pavia but his mother’s joy was short lived when she received news that her first three children had died of the plague in Milan.
Chiara lived apart from Fazio for many years but, later in life, they did marry.
Cardan at first became his father’s assistant but he was a sickly child and Fazio had to get help from two nephews when the work became too much for Cardan.
However, Cardan began to wish for greater things than an assistant to his father. Fazio had taught his son mathematics and Cardan began to think of an academic career.
After an argument, Fazio allowed Cardan to go university and he entered Pavia University, where his father had studied, to read medicine despite his father’s wish that he should study law.
When war broke out, the university was forced to close and Cardan moved to the University of Padua to complete his studies.
Shortly after this move, his father died but by this time Cardan was in the middle of a campaign to become rector of the university. He was a brilliant student but, outspoken and highly critical, Cardan was not well liked.
However, his campaign for rector was successful since he beat his rival by a single vote.
Cardan squandered the small bequest from his father and turned to gambling to boost his finances. Card games, dice and chess were the methods he used to make a living.
Cardan’s understanding of probability meant he had an advantage over his opponents and, in general, he won more than he lost. He had to keep dubious company for his gambling.
Once, when he thought he was being cheated at cards, Cardan, who always carried a knife, slashed the face of his opponent.
Gambling became an addiction that was to last many years and rob Cardan of valuable time, money and reputation.
Cardan was awarded his doctorate in medicine in 1525 and applied to join the College of Physicians in Milan, where his mother still lived.
The College did not wish to admit him for, despite the respect he had gained as an exceptional student, he had a reputation as a difficult man, whose unconventional, uncompromising opinions were aggressively put forward with little tact or thought for the consequences.
The discovery of Cardan’s illegitimate birth gave the College a reason to reject his application.
Cardan, on the advice of a friend, went to Sacco, a small village 15km from Padua. He set up a small, and not very successful, medical practice.
In late 1531 Cardan married Lucia, the daughter of a neighbour Aldobello Bandarini, a captain of the local militia.
ardan’s practice in Sacco did not provide enough income for him to support a wife so, in April 1532, he moved to Gallarate, near Milan.
He applied again to the College of Physicians in Milan but again was not allowed membership.
Unable to practise medicine, Cardan reverted, in 1533, to gambling to pay his way, but things went so badly that he was forced to pawn his wife’s jewellery and even some of his furniture.
Desperately seeking a change of fortune, the Cardans moved to Milan, but here they fared even worse and they had to ignominiously enter the poorhouse.
Cardan was fortunate to obtain Fazio’s former post of lecturer in mathematics at the Piatti Foundation in Milan which gave him plenty of free time and he used some of this to treat a few patients, despite not being a member of the College of Physicians.
Cardan achieved some near miraculous cures and his growing reputation as a doctor led to his being consulted by members of the College.
His grateful patients and their relatives became whole hearted supporters and in this way, Cardan was able to build up a base of influential backers.
Cardan was still furious at his continuing exclusion from the College and, in 1536, he rashly published a book attacking not only the College’s medical ability but their character.
This was not the way to gain entry to the College and not surprisingly Cardan’s application to join in 1537 was again rejected.
However, two years later, after much pressure from his admirers, the College modified the clause regarding legitimate birth and admitted Cardan.
In the same year, Cardan’s first two mathematical books were published, the second The Practice of Arithmetic and Simple Mensuration was a sign of greater things to come.
This was the beginning of Cardan’s prolific literary career writing on a diversity of topics medicine, philosophy, astronomy and theology in addition to mathematics.
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