Girolamo Cardano. September 24, 1501 – September 21, 1576. Italian mathematician, engineer, philosopher, physician, and astrologer. Inventor of the gimbal transmission.


Life and Work:

1. “The goal I sought was to perpetuate my name, because I could achieve it, and not in wealth or idleness, not in honors, not in high positions, not in power,” wrote Girolamo Cardano, an Italian mathematician, philosopher and physician, in his declining years. The true son of the Renaissance has achieved his goal. Today, every car owner knows the name Cardano.


2. An absolutely adventurous scientist, Cardano was born in the first year of the 16th century. He was an illegitimate son of the lawyer Facio Cardano. Shortly before his death, the lawyer married Cardano’s mother; he legalized his son at the same time.


3. Little Girolamo almost died of a disease, but miraculously recovered.


4. From the age of seven, Girolamo worked hard: he assisted his father, a lawyer – carried the bag with papers and books. His father noticed that the boy was smart and taught him to read, write, and count.


5. In the end, Girolamo Cardano received a university education and a doctorate. Later he became a professor of mathematics in Milan, then taught medicine in Bologna, and became famous as one of the best European physicians. At the same time, he did not abandon his studies in other sciences.


6. Not everyone who gets behind the wheel knows that the Cardan shaft was invented by the same Girolamo Cardano who was the first to introduce the numbers that Rene Descartes would call imaginary a hundred years later.


7. It was Cardano who enriched mathematics by publishing the cubic equation solution, which Niccolo Tartaglia secretly told him, as well as Luigi Ferrari’s solution of the quartic equation.


8. The Tartaglia formula was named after Cardano, but in order to restore justice, Cardano honestly wrote in his book Ars Magnae [Great Art], “Scipio Ferro of Bologna well-nigh thirty years ago discovered this rule and handed it on to Antonio Maria Fior of Venice, whose contest with Niccolò Tartaglia of Brescia gave Niccolò occasion to discover it. He gave it to me in response to my entreaties, though withholding the demonstration.”


9. Among his other mathematical achievements is a study on the theory of gambling, which actually marked the beginning of serious works on the theory of probability.


10. Quite in the spirit of the times, Cardano also contributed to cryptography – a special science about keeping information secret. In the field of cryptography, he invented the so-called Cardano grille – a simple encryption device shaped as a square with cut-out cells. As per Cardano’s idea, the encrypted message looked like a normal message, but if the Cardano grille was superimposed on the text, one could read the secret text through the holes.


11. A philosopher and mathematician, Girolamo Cardano, did not give up lucrative medical practice and also worked as an astrologer, which was quite in the spirit of the time. He cast horoscopes for Petrarch, Luther, King Edward VI of England; even the pope himself used his services. By the way, he predicted a long life to Edward VI, and yet he died nine months later. Later, Cardano denied the accusations of an error: supposedly, he was well aware of the king’s imminent death, but the bitter fate of other astrologers had taught him that it was not safe to predict their death to rulers.


12. Ultimately losing all sense of moderation, Cardano cast Jesus Christ’s horoscope and was proclaimed a heretic. The University of Bologna professor of mathematics spent several months in prison and was forced to go to Rome to ask the pope for absolution.


13. Yet, Cardano’s name is forever associated with the Cardan shaft. It is said that when in 1541 King of Spain Charles V triumphantly entered the conquered Milan, Rector of the College of Physicians Cardano was invited to walk next to the royal carriage. In return, grateful Cardano took care of the imperial comfort: he proposed to equip the carriage with a suspension made of two interconnected shafts. That was how his famous Cardan drive was created.


14. In 1531, Cardano married 15-year-old Lucia Bondareni. His wife died early, leaving Cardano two sons and a daughter. Cardano’s eldest son was convicted of murdering an unfaithful wife and executed. The younger son became a gambler, stole money from his father, and was eventually banished from Bologna.


15. Cardano achieved his goal: the complete collection of his works consists of ten volumes printed in small print. He was well-known during his lifetime and is still remembered today. By the way, there is a legend associated with Cardano’s death: allegedly, he predicted the day of his demise, and in order for the prediction to come true, he starved himself to death. Even if it is not true, it is an amazing story, which fits Cardano’s nature perfectly.