Morris Kline (Mathematics in Western Culture, 1953):

It is said that he prognosticated his own death and committed suicide on the date predicted in order to maintain his reputation as an astrologer.


He foretold the date of his own death, and, at age 75, was obliged to abstain from food in order to die at the time he had predicted.

Did Cardano really do this?


1 Answer 1


The short answer is that we do not know for certain. Best I could track it down, the story first appeared in print some thirty years after Cardano's death and may well be apocryphal. On the other hand it seems plausible based on his autobiography.

From Cardano's autobiography 1 it seems that he sincerely believed in his ability to foretell the future, and he relates several dramatic instances of this. For example, when he was a young man, a certain Giovanni Stefano Biffo came to him convinced that Cardano was a chiromancer and insisted he tell him something of his future. Cardano replied that his hanging was imminent. Within a week of this Biffo was apprehended by the authorities, was tortured as he persistently denied his crimes, and was hanged after six months, after having his hand cut off first (2nd ed., chapter 42, p. 155):

Quaedam tamen sic mihi contigerunt, ut causas vix reddere possim, memini me dum essem adolescens, persuasum fuisse cuidam Joanni Stephano Biffo, quod essem Chiromanticus, & tamen nil minus: rogat ille, ut praedicam ei aliquid de vita; dixi delusum esse a sociis, urget, veniam peto si quicquam gravius praedixero: dixi periculum imminere brevi de suspendio, intra hebdomadam capitur, admovetur tormentis: pertinaciter delictum negat, nihilominus tandem post sex menses laqueo vitam finivit, illi prius amputata manu.

In this case Cardano states he could hardly explain the reason for his prediction, but in chapter 47 of the autobiography he mentions that he is attended by a guarding spirit (of the kind that the Greeks called angels), which he believes to be a good and merciful spirit and which is able to foresee what is to befall him (2nd ed., pp. 186-187):

Spiritus assidentes, aut praesidentes (Graeci Angelos apellare soliti erant, quidam minus Latine Spiritus) favisse quibusdam viris pro constanti, ut dixi receptum est: Socrati, Plotino, Synesio, Dioni, Fl. Josepho, sed & mihi. [...] at nobis ut credo bonus & misericors spiritus. [...] cum enim praevideat spiritus quod mihi imminet

Jacques Auguste de Thou, Historiae sui temporis, usually cited as Thuanus in the literature, appears to be the original printed source for the background of Cardano's death. The earliest edition containing the relevant text that I was able to find a scan of dates to 1609 2. In book 62, in a paragraph on Hieronymus Cardanus (= Cardano) among the events of the year 1576 one finds at the end (p. 85, right columm, section B):

tandem, cum tribus diebus minus septuagesimum quintum annum implevisset, eodem, quo praedixerat anno & die, videlicet XI Kal. Oct. defecit; ob id, ne falleret, mortem suam inedia accelerasse creditus.

My translation: "Finally, when he was three days shy of completing his 75th year, he died in the same year and on the same day that he had predicted: the 11th of Kal. Oct; for this, lest he be mistaken, he is believed to have accelerated his death by not eating."

The date of "11th of Kal. Oct." seemed curious to me, but researching this ancient Roman way of dating confirmed it is equivalent to September 21, which is the date given by Wikipedia.

Ephraim Chambers, Cyclopædia: or, An Universal Dictionary of Arts and Sciences, London: 1728, Vol. 1, p. 143:

CALENDS, CALENDÆ, in the Roman Chronology, the first Day of each Month. [...] The Calends were reckon'd backwards, or in retrograde Order: [...] To find the Day of the Calends we are in, see how many Days there are yet remaining of the Month, and to that Number add two: For Example; suppose it the 22d of April; 'tis then the 10th of the Calends of May. For April contains 30 Days; and 22 taken from 30, there remains 8; to which two being added, the Sum is 10.

The paragraph on Cardano from Thuanus was reproduced verbatim in the preface of the first volume of Cardano's collected works 3, so either one may have informed subsequent authors to the present day.

1 Girolamo Cardano (Gabriel Naudé, ed.), De vita propria liber. Paris: Jacques Villery 1643. I consulted a scan of the second edition, Amsterdam: Johannes van Ravesteyn 1654

2 Jacques Auguste de Thou, Historiae sui temporis. Offenbach: Conradt Nebeny 1609 (scan)

3 Girolamo Cardano (Charles Spon, ed.), Opera omnia. Lyon: Jean Antoine Huguetan & Marc Antoine Ravaud 1663 (scan)


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