Why are there astrological signs in some churches and abbeys?

Jewish precedent

Astrological signs are found not only in medieval Christian churches but in far more ancient places such as synagogues of the Talmudic period. The rabbis were ambivalent on their use, as it was denounced by the prophets but also considered useful when put to a godly use. The Jewish Encyclopedia says:

On Joshua b. Levi's "tablets" (third century) it is stated that men born on Sunday will be distinguished, on Monday wrathful, on Tuesday wealthy and sensual, on Wednesday intelligent and enlightened, on Thursday benevolent, and on Friday pious; while those born on Saturday are destined to die on that day.

One rabbinical tradition held:

A man to whom a son was born was met by an astrologer who, on seeing the child, declared that he was destined to become a bandit-chief (ἀρχιληστής) and must be put out in the desert. The father of the child refused until the astrologer's father told him to do just as his son had ordered. The father of the astrologer is God; the astrologer is Sarah; the child is Ishmael; and the father of the child is Abraham.

Christian roots: Pisces and the Sun

Regarding Christianity, the sign of Pisces was used as a symbol of Christ and of the church from early Christian times. The Greek word for fish - ΙΧΘΥΣ (ichthys) - is also an acronym for "Ἰησοῦς Χριστός, Θεοῦ Υἱός, Σωτήρ" (Jesus Christ, God, Savior). In Christian art there is evidence for this dating to the 2nd century. Its use had become widespread by the late 300s. The symbol was reportedly used by Christians to recognize churches and other believers in times of persecution. It may also refer to the miracle of the multiplication of the loaves and fishes. As Christianity grew in the world of Greek and Roman mythology, Christians eventually placed the fish symbol into a Christian astrological system.

Christ was already identified with the Sun by 3rd century in iconography. The assignment of his birthday to the winter solstice further solidified this identification and led to Christ's centrality in Christian astrological systems.

Christian astrological symbolism

Bethany Blankley has written extensively on the significance of Christian astrological signs. She sites especially [The Gospel in the Stars] by the Luther minister and theologian Joseph Augustus Seiss.

• Virgo The first sign in the Christian Zodiac and of prophetic revelation in the stars is Virgo. Virgo is “the Virgin,” whose constellation depicts a woman holding an ear of wheat in one hand and a branch in the other.

• Libra is the sign that points to the Savior who gives his life to redeem his people – and to eternal justice – weighing sin and salvation.

• Scorpio. The ancients believed that Scorpio represented a mighty warrior who was injured in battle, yet still emerged victorious. He fought the Serpent Python and the fire-breathing chimera, among others. This echoes the words of Ps. 91: "You will tread upon the lion and the cobra; you will trample the great lion and the serpent.

• Pisces represents Christ as the original Fisher of Men. It is "the sign of the universal and persecuted church and the continuous outworking of the gospel that multiplies in every generation."

• Aries was usually a ram but also a lamb. In Christian astrology it is the Lamb of God, who was slain, the exalted Son of God who rules over all with his divine dominion and glory.

• Taurus represents the judge and points to Jesus’s role in his second-coming. He is the rushing bull with horns pointing upward, is the sign of coming judgment.

• Gemini has various Christian interpretations. According to Blankley, the the word means “completion” in Hebrew. It thus symbolizes marriage union of Christ and his church.

• Cancer signifies transformation, from putting off the old self and putting on the new (Eph. 4:22-24). As the crab periodically sheds its shell and puts on a new one, believers do likewise.

• Leo is the last sign in the Christian Zodiac. It .fulfills all of what the previous 11 signs have pointed to: Jesus, the Lion of Judah and victor over Satan: “the Lion of the tribe of Judah, the Root of David, has triumphed.”' (Rev. 5:5)

Thus, astrological symbols can be adapted into Christian iconography, whether or not they are accompanied by a practice of divination.

Note: Churches that use astrological iconography do not all follow the above system.