An apology may be needed for the occurrence here and there of passages translated from the _De Vita Propria_ and the _De Utilitate ex Adversis capienda_, passages which some readers may find too frequent and too lengthy, but contemporary opinion is strongly in favour of letting the subject speak for himself as far as may be possible. The date and place of Cardan's quoted works are given in the first citation therefrom; those of his writings which have not been available in separate form have been consulted in the collected edition of his works in ten volumes, edited by Spon, and published at Lyons in 1663. The author desires to acknowledge with gratitude the valuable assistance in the way of suggestion and emendation which he received from Mr. R.C. Christie during the final revision of the proofs. _London, October 1898._ JEROME CARDAN CHAPTER I LIKE certain others of the illustrious personages who flourished in his time, Girolamo Cardano, or, as he has become to us by the unwritten law of nomenclature, Jerome Cardan, was fated to suffer the burden and obloquy of bastardy.[1] He was born at Pavia from the illicit union of Fazio Cardano, a Milanese jurisconsult and mathematician of considerable repute, and a young widow, whose maiden name had been Chiara Micheria, his father being fifty-six, and his mother thirty-seven years of age at his birth. The family of Fazio was settled at Gallarate, a town in Milanese territory, and was one which, according to Jerome's contention, could lay claim to considerable antiquity and distinction. He prefers a claim of descent from the house of Castillione, founding the same upon an inscription on the apse of the principal church at Gallarate.[2] He asserts that as far back as 1189 Milo Cardano was Governor of Milan for more than seven years, and according to tradition Franco Cardano, the commander of the forces of Matteo Visconti,[3] was a member of the family. If the claim of the Castillione ancestry be allowed the archives of the race would be still farther enriched by the name of Pope Celestine IV., Godfrey of Milan, who was elected Pope in 1241, and died the same year. Cardan's immediate ancestors were long-lived. The sons of Fazio Cardano, his great-grandfather, Joanni, Aldo, and Antonio, lived to be severally ninety-four, eighty-eight, and eighty-six years of age. Of these Joanni begat two sons: Antonio, who lived eighty-eight years, and Angelo, who reached the age of eighty-six. To Aldo were born Jacopo, who died at seventy-two; Gottardo, who died at eighty-four; and Fazio, the father of Jerome, who died at eighty.[4]