Girolamo Cardano is one of the most extraordinary characters in the history of mathematics .He was born in Pavia in 1501 as the illegitimate son of a jurist and developed into a man of passionate contrasts. He commenced his turbulent professional life as a doctor, studying, teaching, and writing mathematics while practicing his profession. He once traveled as far as Scotland, and, upon his return to Italy, he successively held important chairs at the Universities of Pavia and Bologna. He was imprisoned for a time for heresy because he published a horoscope of Christ’s life. Resigning his chair in Bologna he moved to Rome and became a distinguished  astrologer, receiving a pension as astrologer to the papal court. He died in Rome in 1576, by his own hand, one story says, so as to fulfill his earlier astrological prediction of the date of his death. Many stories are told of his wickedness, as when in a fit of rage he cut off the ears of his younger son. Some of the stories could be exaggerations of his enemies, and it may be that he has been maligned. His autobiography, of course, supports this viewpoint.

One of the most gifted and versatile men of his time, Cardano wrote a number of works on arithmetic, astronomy, physics, medicine and other subjects. His greatest work is his Ars magna, the first great Latin treatise devoted solely to algebra. Here notice is taken of negative roots of an equation and some attention is paid to computations with imaginary numbers. There also occurs a crude method for obtaining an approximate value of a root of an equation of any degree. There is evidence that he was familiar with “Descartes’ rule of signs”. As an inveterate gambler, Cardano wrote a gambler’s manual in which some interesting questions on probability are considered.