Girolamo Cardano (1501-1576), Italian mathematician. Cardano was born the illegitimate son of a lawyer in Pavia. In 1520 he entered the University of Pavia, then moved to Padua to study medicine. His career was slow to start due to his illegitimate birth, but he did build a considerable reputation. In his spare time he worked on mathematics. In the 1545 book Ars Magna he published solutions to the cubic and quartic equations and posited the idea of imaginary numbers. In later works he introduced the idea of binomial coefficients and the binomial theorem. His work on probability resulted from his considerable skill as a gambler. As an inventor he created the combination lock. He was accused of heresy in 1570 for having cast the horoscope of Jesus, but was released after a few months in prison. This woodcut comes from van Opmeer's Opus chronographicum orbis universi of Antwerp, 1611.