I am simply a Catholic and an astrologer trying to work out exactly what I believe in. Let’s sprint through time.
This is a really galaxy brain, Jupiter in Pisces thought, but I need you to stay with me: It is impossible to extract astrology from the history of Western thought. Astrology was part of every cosmology from the get go. The beginning of the Catholic church, however, needed all of the pagans to calm down in order to establish its power.
The church has never approved of astrology. Aguila Ponticus translated The Bible from Hebrew to Greek. He converted and then was excommunicated from the Catholic church for being an astrologer in the year 120. Someone that important and central to the church was kicked out because he was doing star math.
What was so wrong about seeing the glory of God in the order of the stars? The Old Testament speaks to astrology as being proof of a higher power. Psalm 19 states “The heavens declare the glory of God; the skies proclaim the work of his hands.” The star of Bethlehem is part of the prophecy and proof that Jesus is the son of God. Early Christians were actually afraid of astrology. By banning astrology they were speaking to not only its popularity, but its accuracy. The Bible recognizes the existence and even confirms the function of astrology.
Early astrology was incredibly fatalistic: your fate is set in stone. Modern astrology, however is a little more relaxed. It’s not exactly ethical to tell someone when or how they’re going to die, or that they will experience something specific at a certain date or time. These days we mostly believe in free will. Contemporary stoicism is an anomaly. Christian thought would say we have the choice between good and evil. The apple of Eden was free will. The main rift between the church and astrology is the rift between free will and determinism.
The Catholic church fought paganism to become the prominent state ideology. The Romans worshiped a sun god, and it wasn’t until Constantine the Great’s rule (AD 306–337) that Roman culture began to shift towards Christianity, because he was converted. My favorite historical conspiracy is that Catholicism is actually an assimilation of the cult of Solus Inviticus, a Roman sun cult. Art historians have found both Jesus and David depicted as Solus Inviticus— the sun.
Christianity views all things lunar, natural and bodily as being pagan or susceptible to demonic forces, while all things that are solar, consciously decided, are morally righteous. So Aristotle (Ptolemy’s understudy) & St. Thomas Aquinas claimed that astrology was responsible for the body while religion the soul. Everyone in the renaissance was, like myself, struggling to make their beliefs make sense.
When Bonatti writes about inceptional astrology, or using astrology to decide on a time to begin a venture, he makes sure to go on and on how God honoring it is and how whatever witchcraft astrologers are up to is compatible with both free will and God’s plan. It doesn’t actually check out because it seems like he’s affording himself special privileges. Maybe he deserved them. Reading that introductory passage in his Treatise on Electional Astrology you can tell he’s overcompensating for the guilt he feels as a Catholic. Dante put Bonatti, the most famous astrologer in Italy at the time, in the first circle of hell in Inferno. Simultaneously, Dante himself was using astrology in uniform with his faith, as was the fashion. Just to be clear, Europeans also still thought that the sun revolved around the earth.
The main objection to astrology in most Abrahamic faiths, to this day, is that it should not be used to make predictions. I can see, secularly, how predictions present an ethical dilemma. It can interfere with one’s feeble consciousness and ability to exercise free will. In order for the church and astrology to survive side by side, Renaissance astrology was claimed to only be used to describe natural phenomenon like weather, the tides, what’s happening in the present. There were objections to predictions of wars, plagues, and the realm of the human. I’m not sure how much the court astrologers listened to these objections.
Even after Galileo was excommunicated from the church for saying that the earth revolves around the sun, people were still trying to consolidate their faith with astrological cosmology. The most famous astronomers— Brahe, Galileo, Kepler— were court astrologers for their respective nations. Astrology found a way to coexist with the church, since it was relegated to the realm of nature. Predictive astrology however still remained morally contested, even heretical.
Just before the enlightenment, English astrologer William Lily wrote a doctrine on horary astrology called Christian Astrology. He was really not trying to get into any trouble, hence the title. He did, however, predict The Great Fire of London and then was tried because they thought he started the fire himself.
From the time of the enlightenment onward, astrology was simply a niche interest in the West. People were too busy trying to develop penicillin and pasteurized milk to care about what the stars were saying. Astrology still existed, as it always has and always will, however it was not as fashionable or popular since it is about as incompatible with the scientific method as the stock market.
19th century Spiritualism revived an interest in astrology, at least in the US. The church maintains its stance against divination:
All forms of divination are to be rejected: […] Consulting horoscopes, astrology, […] all conceal a desire for power over time, history, and, in the last analysis, other human beings, as well as a wish to conciliate hidden powers. They contradict the honor, respect, and loving fear that we owe to God alone.
— Catechism of the Catholic Church
I can’t say I fully disagree.