The Beheading of Jerome Cardan’s Son

The Italian astrologer Jerome Cardan (1501 – 1576), aka Gerolamo Cardano, was one of the greatest mathematicians of the Renaissance. Because he was often short on cash, he developed probability theory to help him win at gambling. Cardan was born on September 24, 1501 in Pavia, Italy.

The natal chart of Jerome Cardan used by Morinus in Astrologia Gallica (1661)

In his autobiography he writes: “I was born normally September 24, 1501 when the first hour of the night was more than half run but less than two-thirds.” The first hour of the night belonged to Mars and ran from 5:31 pm to 6:34 pm LMT in Pavia, but I’m not sure how time was measured in Pavia (probably LAT) when Cardan was born. Based on his reading of the works of Cardan, Morinus cast Cardan’s natal chart with a birth time of about 6:29 pm LMT. This is consistent with Cardan’s description of his own horoscope in his autobiography in which he writes that Venus rules his Ascendant (Taurus rising), Sun lies in the 6th and Moon in the 12th Campanus houses, and Jupiter is in the Ascendant (rising sign). There is a typo in the autobiography which states the year was 1500 but the description of the chart only makes sense if he was born in 1501.

Jerome Cardan had a difficult life. He was born illegitimate and in ill health. Despite his obvious brilliance, his bastard status impeded advancement in his career. He had hoped to work in Milan but due to social opprobrium he ended up practicing in Gallarate, Italy (45N40, 8E48) not too far from Milan. His son Gian Battista was born here.

On 20 December 1557 Cardan had a premonition. He spent the night sleepless and felt that his bedroom was shaking as if in an earthquake. The next day he asked people in the market if they had the same experience but was met with denial. When he returned home, his servant informed him that his 23-year-old physician son Giovanni Battista had married an apparently disreputable girl, Brandonia Seroni, who had no dowry. Cardan writes: “that was the beginning of all misfortune.” The son eventually realized that Brandonia had been cheating on him and had given birth to her lover’s children instead of his own, so he allegedly poisoned her with arsenic and was convicted of murder. Giovanni Battista Cardan was imprisoned on 17 February 1560 and beheaded on 14 April 1560 NS (but some sources give 17 April 1560 NS as the date of the execution).

The story of Cardan’s beheaded son became well known and was discussed by many famous astrologers in later centuries. Placidus reviewed the chart in one of his books in the 17th century. Reproduced below is the natal chart of Cardan’s son from the writings of Placidus translated into English by John Cooper.

Natal chart of Giovanni Battista Cardan, the son of Jerome Cardan, according to Placidus. The native was born in Gallarate (45N40, 8E48), so the latitude of 44 degrees is either a typo or represents the nearest available entry from available tables of the time. The birth time of 8:30 pm is in LAT and corresponds to about 8:28 pm LMT. Below is a modern calculation of this chart.
Giovanni Battista Cardan’s natal chart. He was beheaded for killing his wife with arsenic because she was cheating on him. He died of beheading by the sword on 14 April 1560 NS in the dungeon where he was imprisoned.

Is there symbolism in the birth chart which suggests a violent death? Yes, there is. Jupiter, the Ascendant ruler, closely opposes a peregrine Mars in the 8th house of death. Jupiter also conjoins Pluto which opposes Mars in the 8th, suggesting a violent demise. Mars also rules the 12th of self-undoing and the 4th of endings and the grave A debilitated Saturn in Cancer rules the wife’s 8th and occupies the native’s 8th of death. Uranus, a planet of sudden disruptive events, applies to conjoin the 8th cusp. The Moon, which rules the 8th, is peregrine in Gemini (the detriment of Asc-ruler Jupiter) and is also in aversion to the 8th. The antiscion of the Moon lies at 9 Cancer 25, conjunct the true lunar north node and opposite the true lunar south node. Such nodal contacts are often considered “fateful” degrees.

The young physician died at age 25 about a month before his 26th birthday. In his solar return he was in a 2nd house (Capricorn) profection year. The 2nd house contains the Jupiter/Pluto conjunction which opposes Mars in the 8th, and Saturn (ruler of Capricorn) occupies the 8th, so that these natal configurations, which signify a violent death, become activated during his 25th year.

Giovanni Batistta’s primary directions by Placidus semi-arc at the Naibod rate without latitude for this period, as calculated in Janus 5 software, are the following:

The closest primary direction to the date of his beheading at the Naibod rate is the square of the Sun conjoining Mars in the 8th house on May 26, 1560. Mars (a symbol of violence and severing) occupies the 8th of death and the Sun (a symbol of the life force) rules Leo intercepted in the 8th house. Not listed above is that the primary directed Moon (ruler of the 8th of death) opposes the natal 12th house cusp (confinement, self-undoing) on the date of his beheading.

My preferred rate for primary directions is the midpoint of the Ptolemy and Naibod rates. Below are the primary directions at this midpoint rate. Custom point 1 refers to Caput Algol, the fixed star associated with beheading.

This list was generated with the same parameters as the previous one but at a rate midway between that of Ptolemy and Naibod. It is noteworthy that by primary direction the square of the Sun conjoined natal Mars in the 8th house on 19 March 1560 and then the sextile of Caput Algol arrived at Mercury in the 7th house on 5 April 1560, both aspects perfecting very close to the date of his beheading on 14 April 1560.
(In 1560 Caput Algol had an ecliptic longitude of 19 Taurus 40.)

Addendum, 2 April 2020:

Pp asked below about the significance of the young Cardan’s Mars lying in the 8th quadrant house but in the 9th whole sign house. Initially, I had no idea why that symbolism should appear in his natal chart, but it occurred to me that the 9th house often signifies one’s in-laws (the siblings and kin of the spouse), so I looked up whether his wife’s siblings played a role in the death. Morinus combined the significance of the quadrant house placement of a planet with its whole sign house position to delineate a chart. Fortunately I came across a biography of Jerome Cardan by William George Watters (1898), which clarifies the situation. Below I have copied and pasted the relevant paragraphs which indicate the major role the in-laws played in this drama. Jerome Cardan learned from his son’s servant that Gian Battista had suddenly decided to marry:

Gian Battista then asked his servant to help him to carry out

NOTE: After reading the above biography, I have recalculated the birth chart of Cardan’s son. The modern chart above is calculated with the same Ascendant as given by Placidus. Originally I had set the chart for Pavia but upon reading the biography of Cardan I learned that his son was born in Gallarate (not Pavia as I originally thought), so I recast the chart for that city using the same Ascendant as the chart given by Placidus. Because the Placidus version of the chart that appears in Cooper’s 1816 translation is set for a latitude of 44N rather than 45N40, the Placidus house cusps of the modern chart are slightly different from the ones in Cooper’s early 19th century text.

Based on this recalculated chart, I looked at the primary directions for the time of his execution. Using Placidus semi-arc at the Naibod rate with latitude of the planets, I found that for a rectified birth time of 8:27:21 PM LMT at Gallarate, the primary direction of the SQUARE of the SUN conjoins natal MARS in the 8th house on 14 April 1560 NS, the date of his beheading.

About Anthony Louis

Author of books about astrology and tarot, including TAROT PLAIN AND SIMPLE, HORARY ASTROLOGY, and THE ART OF FORECASTING WITH SOLAR RETURNS.
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7 Responses to The Beheading of Jerome Cardan’s Son

  1. VenusCazimi SpicaRising says:

    Was this posting inspired by transit Venus on Algol?

    Last night, on a very popular satirical TV show, there was one political episode that seemed to have been inspired by this transit too.

    • It was not consciously inspired by Venus transiting Algol this week. I’ve been reading about topocentric primary directions and in that context was looking at classic charts with which to test various techniques. It may be that Venus conjunct Algol by transit on March 30th played a synchronistic role in my coming across this chart.

  2. Pp says:

    Mars is in 9th by whole sign house

  3. I will add an addendum to address the 9th house question. After reading your comment, I wondered whether his wife’s siblings played a role in the deaths.

  4. Lesley says:

    looking at the chart id expect him to have a nice inteligent wife although venus and moon rule evil houses . Mars rules 5th of children,the cause of murder and eventually his death

  5. Dan says:

    There was actually a book that came out about Cardano. I emailed the author about coming on my new podcast, but he said he wasn’t publicly speaking with astrologers.

  6. Hi Dan, Thanks for the info.

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