CARDANO, GIROLAMO

One of the most prolific writers of sixteenth-century Italy, Girolamo Cardano is best known for his contributions to medical literature and mathematical schol­arship. He was born in Pavia on 24 September 1501, the illegitimate son of Fazio Cardano, a jurisconsult, and Chiara Micheri, a younger widow. According to Cardano, the physiological, emotional, and astrological circumstances sur­rounding his nativity were less than auspicious. His parents had attempted to abort the pregnancy through drugs, and he was prone to chronic poor health from his early childhood. Neither parent lavished affection on their son, but Girolamo seems to have experienced a somewhat warmer relationship with his father than with his mother.

It was Fazio who taught his son the rudiments of arithmetic, geometry, and even some principles of the astrological sciences. Instead of the legal career that his father envisioned, however, Cardano gravitated toward medicine. He began his studies at Pavia when he was nineteen, then continued at the University of Padua, where he took his doctorate in medicine in 1526. His first professional appointment was in the town of Saccolongo, near Padua. While he was in res­idence there, in an act typical of his profound belief in portents and signs, he married Lucia Bandarini because of her likeness to a woman in one of his dreams. The marriage produced three children.

After a brief stay in Gallarate, Cardano moved his family to Milan in 1534, where he taught mathematics, astronomy, dialectics, and Greek while he was employed as the physician of the city's poorhouse. The success of his medical practice quickly made him Milan's most esteemed physician; his reputation across Europe would eventually be second only to that of Andreas Vesalius.* By his fifties, Cardano had already received invitations from several European courts, most of which he declined. In 1552, however, he undertook the principal journey of his life when he traveled to Scotland to treat John Hamilton, the asthmatic archbishop of Edinburgh, visiting the English court on his return.He held the chair in medicine at the University of Pavia from 1543 to 1559 (with a seven-year interruption) and also at the University of Bologna from 1562 to 1570.

Much of Cardano's notoriety was the product of his long and extraordinarily prolific publishing career. Including his medical treatises, he wrote over 130 printed works on subjects ranging from music to morality and from gambling to astrology. His encyclopedic De subtilitate found a widespread audience and saw ten reprints during his lifetime. His Practica arithmeticae (1539) and the celebrated Ars magna or The Rules of Algebra (1545) established him as a mathematician of considerable ability. The latter work also sparked Niccolo Tartaglia's* bitter dispute with Cardano, to whom he had confided his solution for cubic equations. When Cardano learned that Tartaglia's accomplishment du­plicated the work of an earlier mathematician, he published it (with attribution) in Ars magna. The controversy aside, Ars magna is frequently cited as the signature work of his body of publications.

Cardano's professional felicity did not translate to his domestic affairs, how­ever. In 1560 he unsuccessfully petitioned to save his eldest son from execution for poisoning his wife. His daughter's premature death and his younger son's criminal behavior also stained much of his life with grief. In 1570, while teach­ing at Bologna, he was arrested by the Inquisition for heresy, possibly for having cast and published the horoscope of Christ. He recanted and was thereafter prohibited to teach or publish. Afterwards, he moved to Rome, where he was pensioned by Pope Pius V for the remaining years of his life. At the age of seventy-four, Cardano wrote his autobiographical De propria vita (The Book of My Life), a candid assessment of his life, habits, and work, and died later that same year on 20 September 1576.

M. Fierz, Girolamo Cardano (1501-1576): Physician, Natural Philosopher, Mathema­tician, Astrologer, and Interpreter of Dreams, trans. Helga

Niman, 1983. N. Siraisi, The Clock and the Mirror: Girolamo Cardano and Renaissance Medicine, 1997.

(1501-1576)

   Italian physician, mathematician, and natural philosopher. Born in Pavia and educated there and at Padua, he supported himself during his student years as a gambler. One of his later writings, Liber de ludo aleae / Book on Games of Dice, presented a sophisticated discussion of the mathematics of probability, though it had little influence since it was not published until the following century. After graduation, he practiced medicine near Padua and in 1534 moved to Milan, first as a teacher of mathematics and later as a medical practitioner.From 1543 to 1560 he was professor of medicine at the University of Pavia. Cardano's interests extended to many branches of natural philosophy, including mechanics, geology, and hydrodynamics. He realized that the trajectory of a projectile is a parabola; he noted that the presence of marine fossils on dry land proves that mountainous regions had once been ocean floor; he suggested that the earth's water is constantly recirculated from rain to rivers to oceans to clouds and back to rain.

   Cardano was especially gifted as a mathematician. His first mathematical publication, Practica arithmeticae / Arithmetical Practice (1539), showed great skill in manipulating equations. He was one of a number of contemporaries who studied quadratic equations, and his book Ars magna / The Great Art (1545) summarized his own work and that of several others on that topic, though it also involved him in a bitter controversy with Niccolo Tartaglia even though he gave Tartaglia full credit for his pioneering contributions. In 1560 Cardano moved from Pavia to Bologna. There he was imprisoned in 1570 by the Roman Inquisition on suspicion of heresy, but he was released and spent his final years at Rome, supported by a papal pension.