For the Glory of God – Of Renaissance Popes and their Astrologers

We begin our story with Guliano della Rovere. As Pope Julius II, he was head of the Roman Catholic Church and ruler of the Papal States from 1503 to his death in 1513. He also was an ardent follower of astrology. His personal astrologer, Antonio Campanazzo, postponed Julius’ coronation to make sure that the event would fall on an auspicious date. During his time in office, Julius ordered the demolition of the sacred early Christian basilica, built over the tomb of St Peter. It was to be replaced with the new Saint Peter’s Basilica, which was to become a world famous landmark. Again, Julius’ astrologers were called in to elect the most auspicious moment for the laying of the foundation stone. The date the astrologers elected was 18 April 1506.

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The chart above, published by Luca Gaurico, who we will talk about in more detail later on, shows the moment the foundation stone was ritually put into position. In her paper The Foundation Horoscope(s) for St. Peter’s Basilica, Rome, 1506, (1) Mary Quinlan-McGrath proposes that the astrologers in charge did not only elect the most auspicious moment, but that they also managed to harmonise the election chart with the Thema mundi, the birth chart of Christ, and the Pope’s own nativity. Another astrologer, Antonio Campanezzo, sent a prediction to Julius II, foretelling his long and successful reign. He also admitted that it had not been entirely legal to cast the Pope’s nativity. Little had he to fear because Julius was pleased to seek his advice, furthermore asking for an election for his coronation day, the foundation of a castle, and the erection of his own statue in Bologna.

We leave  Julius II and move on to his successor, Giovanni de Medici, who was Pope Leo X between 1513 and 1521. Here we meet Luca Gaurico, the man who provided the foundation chart, pictured above. Gaurico was an astrologer, astronomer, a data collector and a mathematician, who lived in Italy between 1475 and 1558. He served as court adviser to Catherine de Medici, as well as being astrologer to several popes.  Gaurico successfully predicted the accession to the papacy of Catherine’s great-uncle Giovanni de Medici when the latter was 14. He also predicted Catherine’s uncle Giulio de Medici’s involvement in political struggles. Giulio de Medici was to later become Pope Clement VII. We will meet Gaurico again later on, when he will become unofficial astrologer to the papacy under Pope Paul III. But back now to Pope Leo X, whose personal astrologer was a man called Franciscus Priulus. We do not know much about Priulus,  except that he wrote a book about his patron’s birth chart, and also that he had apparently been able to tell Leo many facts about his childhood, and secrets which only the Pope himself knew. Leo claimed that his astrologer was able to make predictions that were accurate to the very hour. He was very much taken with Priulus’ abilities and remarked that astrology, which had once been extinct, had been ‘revived through this extraordinary man’. After Priulus’ death, Leo employed the astrologers Pellegrino Prisciano of Ferrara, Thomas Philologus, Castaneolus, Nifo, and Bernard Portinarius. It was commonly known that Pope Leo X was literally addicted to astrology, which meant that authors and writers saw no problem in addressing him with astrological jargon. ‘Under your auspices, o Leo, the malign influences of the stars have vanished, and Jupiter has not poured upon us any but the propitious fires of his purest rays’, wrote Girolamo Fracastoro in his medical poem Syphilis. With all that praise being heaped upon him, it doesn’t come as a surprise that Leo eventually founded a chair of astrology at the University of Rome, the Sapienza.

We now move on to Pope Adrian VI, who showed little excitement when elected Pope because astrological studies he had conducted in his youth had already promised that he would become Pope. He was succeeded by Pope Clement VII, who, as well as his predecessor, did not object to having astrological almanacs dedicated to them. 

Next, and of great interest to our humble investigation, is Pope Paul III , born Alessandro Farnese, who was head of the Catholic Church and ruler of the Papal States from 13 October 1534 to his death in 1549. He was so much in favour of astrology that he encouraged astrologers to come to Rome where they could work under his protection. The by now quite familiar astrologer Luca Gaurico predicted twice, in 1529 and 1532, that Farnese would become Pope. When he became Paul III, he knighted Gaurico and made him Bishop of Giffoni. The astrologer also correctly predicted the Pope’s death to the day as well as the illness he would die of. Paul III asked Gaurico to determine the most auspicious time at which the cornerstone of a new building in the neighbourhood of St Peter’s Basilica should be laid. Legend has it that Gaurico arrived at the scene in great pomp. An assistant, the astrologer Vincentius Campanatius of Bologna, was brought in as Gaurico’s splendidly robed assistant. He had to inspect the sky with his astrolabe, crying out in a loud voice when the moment had arrived for a cardinal to lay the foundational marble slab. Paul III was widely known to be in favour of astrologers. Works of astrological nature were dedicated to him, and he was praised by Vincentius Franciscucius for ‘restoring the reputation of astrology which had lain for so long in the darkness and barbarism of past centuries’. Later on, Paul was assured by the astrologer Marius Alterius that in his 83rd year he would have great success with women, delivering erotic diversions ‘… which will overwhelm your spirit with singular pleasure’ and that he would live to the ripe old age of 93. The only problem was that Paul III died when he was 81. 

Thorndike states in his monumental work A History of Magic and Experimental Science (2), that Paul III and Pius IV or even Gregory XIII, who was the immediate predecessor of Sixtus V, had a favourable attitude towards astrology. A figure of the nativity of Gregory XIII by Alfonso Ceccarelli can be found in MS Vatic. lat. 6253, fol. 26. (vol.VI, p156).

The next Pope of interest to us is Marcellus II, born Marcello Cervini degli Spannochi. When Marcellus’ father saw his son’s birth chart, he predicted that Marcellus would be installed in the papal chair, but in a way the he would and wouldn’t be Pope at the same time. This turned out to be true because Marcellus died within 22 days of being elected.

His successor, Pope Paul IV, born Gian Pietro Carafa, was head of the Catholic Church and ruler of the Papal States from 23 May 1555 to his death in 1559. It is believed that he received unsolicited astrological predictions concerning his death. Frightened by these, he ordered the expulsion of all astrologers from the Papal States in 1556. Paul IV was the Pope who wrote the infamous bull Cum Nimis Absurdum, which ordered the creation of a Jewish ghetto in Rome. He also introduced the Index Librorum Prohibitorum, also known as the ‘Index of Prohibited Books’ to Venice. Under his authority, some books about divinatory astrology, as well as books written by Protestants were banned, together with Italian and German translations of the Latin Bible.  

The next Pope we have to talk about is Pius V, born Antonio Ghislieri (from 1518 called Michele Ghislieri, O.P.). He was head of the Catholic Church and ruler of the Papal States from 8 January 1566 to his death in 1572. Pius V is also venerated as a saint of the Catholic Church. We think that he must have been interested in astrology, because he owned an astronomical desk clock, built by Giovanni Maria Barocci in circa 1570. One of the clock’s dials shows astrological aspects.

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What is of particular interest to us is the fact that he is highly notable for his role in the Council of Trent. The Council of Trent, which defined Catholic doctrine, established that books  dealing with natural, as well as judicial astrology were not censored or banned. Only astrological works asserting that their predictions were certain, were condemned.  This was summed up in ‘Rule IX’ of the Ten Rules on the Prohibition of Books. We will come back to this a little bit later. Pius V also declared Thomas Aquinas a Doctor of the Church. It is said that Aquinas’ influence on the Church was so strong, that during all sessions of the Council of Trent his Summa Theologica was placed alongside the Bible on the main altar. Aquinas’ views on astrology, as found in Summa Theologica, are as follows:

“The majority of men follow their passions, which are movements of the sensitive appetite, in which movements of the heavenly bodies can cooperate: but few are wise enough to resist these passions. Consequently astrologers are able to foretell the truth in the majority of cases, especially in a general way. But not in particular cases; for nothing prevents man resisting his passions by his free-will. Wherefore the astrologers themselves are wont to say that ‘the wise man is stronger than the stars’ [Ptolemy, Centiloquium, prop. 5], forasmuch as, to wit, he conquers his passions.” (Prima Pars: 115:  Reply to Objection 3)


The next Pope we are interested in is  Sixtus V, born Felice Piergentile. He was head of the Catholic Church and ruler of the Papal States from 24 April 1585 to his death in 1590. On 5 January 1586, Pope Sixtus V issued Coeli et terrae, a papal decree wherein he condemned all forms of judicial astrology. He wrote:

“… They [the astrologers] take the moment a child was conceived, or its birthday, or some other ridiculous observation and note of times and circumstances and, from this, rashly presume to foretell, judge and pronounce upon each person’s rank and situation, how his life will proceed … other fortunate and unfortunate events which may come his way … Therefore, WE condemn and reject all types of divination … by this decree, which will be forever valid, and by Our Apostolic authority, We decree and declare against astrologers … and any others who practice the art of what is called judicial astrology (with the exception of those who make predictions in relation to agriculture, navigation and medicine); also against those who dare to cast and interpret people’s birth- horoscopes with a view of foretelling future events – be these contingent, successive or fortuitous – or actions dependent on human will, even if the astrologer maintains or testifies that he is not saying anything for certain …”

It seemed that suddenly, in theory and, at least for the time being, the practice of natal-, mundane-, horary-, and electional astrology was forbidden. It turned out though, that the papal bull did not in any way curtail the practice of the art. In 1588, for example, Gallucicus (Giovanni Paolo Gallucci) dedicated his Theater of the Universe, in six books, a work on astrology, to Sixtus V. It was reprinted twice in Italy over the next 20 years and three times in the Spanish translation. The 1590es witnessed an unbroken popularity of natural and judicial astrology, particularly amongst the clergy. Corinne Mandel writes in her paper “Starry Leo”, the Sun and the Astrological Foundations of Sixtine Rome that there is evidence that ‘Sixtus V actually created the mythology of his life and pontificate on the basis of his natal chart’ (p17). (3)

In August 1590, Sixtus V died either of malaria or he was poisoned. He was superseded by three short-lived Popes,  Urban VII, who was the shortest lived Pope in history with only 12 days in office, Gregory XIV, and Innocent IX. Stability returned in 1592 with the election of Pope Clement VIII, born Ippolito Aldobrandini. He was head of the Catholic Church and ruler of the Papal States from 2 February 1592 to his death in 1605. Although the bull of Pope Sixtus V was officially accepted, it was ignored when it came to its application in regards to book censorship. The Index of 1590 agreed with the bull’s distinction between judicial and natural astrology, but still kept the wording of 1559 and 1564. In fact it was prohibiting ‘necessitating’ predictions, but didn’t prohibit ‘inclining’ ones. The Index of 1593 (already under Clement VIII) only added ‘interpretative provisions’, and the Index of 1596 reiterated the rules from 1564 word for word. In other words, Coeli et terrae, the bull of 1586, did not affect the practice of censorship at all! Repeatedly pressed by bishops of the Congregation of the Inquisition in 1592 to make a clear statement, the Pope decided that, without modification to the bull, ‘It was decreed … that books of Astrology were to be suppressed according to rule IX: and accounts should be taken of Sixtus V’s bull’. To understand this better, we have to take a quick look at Rule IX of the Ten Rules on the Prohibition of Books promulgated under the signature of Pope Pius V, at the Council of Trent, which I mentioned above. Rule IX states

“The bishops shall diligently see to it that books, treatises, catalogues determining destiny by astrologers, which in the matter of future events, consequences, or fortuitous occurrences, or of actions that depend on the human will, attempt to affirm something as certain to take place, are not read or possessed. Permitted, on the other hand, are the opinions and natural observations which have been written in the interest of navigation, agriculture or the medical art.”

Basically, anything not reaching the level of divination (i.e. predictions born of necessity and therefore certain to happen) could be published. Therefore, judicial astrology avoiding prediction with certainty, was allowed under Rule IX. 

But back now to Clement VIII and his problems with the bull. Although he had stated that Rule IX was to be observed, some uncertainty remained. In 1597 the cardinals of the Index submitted the issue to the Pope again ‘because of the problems arising almost every day’. Strictly observed, for example, the complete prohibition of judicial astrology would have put Arabic and Greek classics on the index. This was something that hadn’t been covered under Rule IX before. For these and other practical reasons, the members of the Congregation of the Index wanted to get some form of reassurance concerning the non-observance of Coeli et terrae. Therefore they put the question before the Pope ‘whether the constitution relative to judicial astrology was still in force’. The answer they received was a resounding ‘no’. Reason for this was that Pope Clement was opposed to the bull and it had not been accepted as valid by the Congregation of the Decretals. Also, the rules of the Congregation of the Index contradicted it.

Now we take a 36 year leap forward to Pope Urban VIII, who was head of the Catholic Church and ruler of the Papal States from 6 August 1623 to his death in 1644. He was the Pope responsible for summoning Galileo to Rome in 1633 to recant his work. It was known that Urban was opposed to Copernican heliocentrism and for this reason, he ordered Galileo’s second trial. The astronomer had just published his Dialogue Concerning the Two Chief World Systems. What probably did not help was the fact that in the dialogue the character named “Simplicio” presents similar arguments to those of Pope Urban VIII. Two years earlier, in 1631, Urban issued his bull Inscrutabilis iudiciorum Dei altitudo, seemingly reaffirming the bull of Sixtus V, pointing out that nobody was immune from its prohibitions. It  went as far as to include threats of death and confiscation. Thorndike  infers from this that ‘ … the decree against astrologers had not been well enforced in the interim’, and ‘ … the fact that Urban VIII in particular forbids predictions concerning political and ecclesiastical matters, especially the life of the Pope … makes one suspect that it was the boldness of the astrologers in forecasting such matters which elicited the bull, and that it was such predictions which would actually be most likely to be punished.’ (vol.6, p171). We now know that Urban was an ardent student of astrology. His personal astrologer had established that he, Maffeo Barberini, was born to be the leader of the church. After all he was elected during a Sun – Jupiter conjunction in Leo, with Virgo rising, and so the sun became the emblem of his papacy. 

Urban VIII bi wheel

Astrology became an obsession to Urban, and is said that he demanded natal charts of all his Cardinals to determine how long their lifespan would be. Once in possession of the charts, he then proceeded to openly predict the dates of their deaths. But all this was about to change when from 1626 astrologers began to predict his own imminent death. In 1629, the influential astrologer Father Orazio Morandi, abbot of the monastery Santa Prasaede in Rome, predicted Urban’s death to occur the following year. Brendan Dooley has published a book, Morandi’s Last Prophecy and the End of Renaissance Politics (4), that tells the story. After Morandi had astrologically established the time of Urban’s death, he sought confirmation from other astrologers. Rumours began to spread, and cardinals began to arrive, preparing for a papal conclave to elect the next pope. When Urban received the news, he was outraged and Morandi was arrested immediately. Soon after his imprisonment, he died under suspicious circumstances. The Warburg Institute scholar D. P. Walker writes in his Spiritual and Demonic Magic (5) that these rumours were welcomed and encouraged by the Spanish. Annoyed by the Pope’s pro-French policy, they hoped to frighten Urban to death. According to Walker, the content of Inscrutabilis iudiciorum shows how scared and worried Urban VIII must have been. Although confirming Coeli et terrae in general terms, the only practices the new bull specifically condemned were predictions of the deaths of princes and especially of Popes. But Urban did not only issue his bull to protect himself. He also enlisted the help of the Dominican friar, philosopher, theologian, astrologer, and poet Tommaso Campanella. As early as 1628, during the January lunar eclipse and the solar eclipse in December, and again in 1630, Campanella and the Pope were reportedly engaged in nocturnal magical rites. Walker writes that they:

‘… sealed the room against the outside air, sprinkled it with rose-vinegar, … and burnt laurel, myrtle, rosemary and cypress. They hung the room with white silken cloths … two candles and five torches were lit, representing the seven planets. … There was Jovial and Venereal music, which was to disperse the pernicious qualities of the eclipse-infected air. … They used stones, plants, colours and odours, belonging to good planets. They drank astrologically distilled liquors ’. (p207)

Considering that the Pope lived on until 1644, we cannot fault the abilities of Campanella, who wrote the ritual especially for this purpose and occasion.

  1. Quinlan-McGrath, Mary: The Foundation Horoscope(s) for St. Peter’s Basilica, Rome, 1506: Choosing a Time, Changing the Storia, ISIS, vol.92, nr.4, December 2001.
  2. Thorndike, Lynn: A History Of Magic And Experimental Science: During The First Thirteen Centuries Of Our Era, 8 vols., Colombia University Press (1958)
  3. Mandel, Corrine: “Starry Leo”, the Sun and the Astrological Foundations of Sixtine Rome, RACAR: revue d’art canadienne / Canadian Art Review, Vol. 17, No. 1, 1990
  4. Dooley, Brendan: Morandi’s Last Prophecy and the End of Renaissance Politics, Princeton University Press, Princeton 2002
  5. Walker, D. P. : Spiritual and Demonic Magic, Studies of the Warburg Institute, vol.22, The Warburg Institute, University of London, 1958



2 thoughts on “For the Glory of God – Of Renaissance Popes and their Astrologers

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