Written in the Stars: Astronomy and Astrology in Medieval Manuscripts

Humankind has always looked to the sky in wonder, with a desire to understand our place in the universe. Eclipses, comets, and star and planet sightings mesmerize us and inspire awe. In the medieval world, from about 500 to 1500, astronomy was a required field of study. From London to Baghdad and beyond, students of medicine, philosophy, and even theology carefully observed the astrological relationship between the 12 signs of the zodiac and one’s physical, mental, and spiritual well-being. Indeed, peoples of many religions believed that the radiant sun, full moon, twinkling stars, and distant planets held great power over their lives, the seasons, and daily activities.

The Getty Center’s exhibition The Wondrous Cosmos in Medieval Manuscripts (April 30 to July 21, 2019) invites you to marvel at the complexity of the celestial realm in European faith and science traditions, with a glimpse at how similar beliefs held sway in Asia, Africa, and the Americas. The illuminated manuscripts show how astronomy and astrology infused everyday life in the Middle Ages, from medicine to religion and beyond.

Astronomy and Astrology

Faith and science—or the humanities and the sciences—were closely aligned in the Middle Ages. Universities across Europe organized their courses and bookshelves around the seven liberal arts: grammar, rhetoric, logic, music, geometry, arithmetic, and astronomy. As the study of the physics of cosmic orbs and other astral phenomena, astronomy was the foundation for astrology, which seeks to correlate these celestial events with happenings on Earth and individual human affairs. By looking at a range of manuscripts containing texts from astronomy and astrology, the exhibition shows the close relationship between the two.

A cutting from the manuscript The Consolation of Philosophy, written by the fifth- to sixth-century writer Boethius, depicts the author speaking to Philosophy, who leads personifications of each of the aforementioned subjects. The last personification is Astronomy, who gazes up at the sun and moon while holding an armillary sphere, a model of the celestial universe.

Another example from Boethius proposes a relationship between music and astronomy. In a scheme known as “the music of the spheres,” Boethius assigned musical value to each of the known planets based on their positions in the sky relative to the Earth, similar to a musical scale. The basic scale begins with the Moon, followed by Mercury, Venus, the Sun, Mars, Jupiter, and Saturn. An illumination in an early-fifteenth-century copy of the text shows Boethius explaining his method to a group: a hovering golden orb indicates a musical tone, the diatessaron (a fourth above the tone), and diapente (a fifth above). (The movement of the celestial spheres has inspired composers and musicians to the present, from Palestrina to Beyoncé, and from Franz Joseph Haydn to Nico Muhly, Sufjan Stevens, and Ariana Grande. See astrophysicist and musician Matt Russo’s brilliant TEDx talk, “What Does the Universe Sound Like? A Musical Tour” for a captivating demonstration of this long history.)

The Influence of the Stars

All year round, from sunrise to sunset, people in medieval Europe regulated their lives based on the position and movement of heavenly luminaries (the sun and moon), the planets, and the stars that constitute the signs of the zodiac. Even the language for the days of the week shows this influence, with Latin-based names derived from planets:

• Monday is moon day, and moon in Latin is luna, from which we get lundi (French), lunes (Spanish), and lunedì (Italian).
• Tuesday is Mars-day (mardi, martes, martedì).
• Wednesday is Mercury-day (mercredi, miércoles, mercoledì).
• Thursday is Jupiter-day (jeudi, jueves, giovedì).
• Friday is Venus-day (vendredi, viernes, venerdì).
• Saturday is Saturn-day, but in Latin languages is the Judeo-Christian day of Sabbath (samedi, sábado, sabato).
• Sunday is the day of the sun or day of the Christian God when derived from Latin.

A manuscript with various astronomical texts—called a miscellany—illustrates the degree to which cosmic forces were thought to influence one’s life. It features a series of watercolors personifying planets or celestial bodies, including the Sun as an emperor, the Moon as a woman, Mars as an armored knight, Mercury as a doctor, Jupiter as a bishop, Venus as a lady holding an arrow of love, and Saturn as an elderly man. Each figure is associated with a color and adorned accordingly: golden yellow (the Sun), green (the Moon), red (Mars), silver (Mercury), blue (Jupiter), white (Venus), and black (Saturn).

Several pages later, circular diagrams declare the relationship between the luminaries or planets and the days of the week. For example, “Friday belongs to Venus.” At the center of the concentric circles is a representation of the planet named after the Roman goddess of love and beauty imagined as a white, six-pointed burst emanating red rays.

The 24 hours of the day—indicated by Roman numerals I through XII repeated twice—are color-coded to the heavenly body that governs quotidian activities. Thus at noon on Friday we are under the influence of the moon, whereas at six o’clock in the evening Mars holds power over us. Representations of the zodiac signs Pisces, Libra, and Taurus are also found on these pages, each accompanied by planets or a luminary (Pisces features Jupiter and Mars, Libra the moon, Saturn, and Jupiter, and Taurus Mercury, the Moon, and Saturn).

Month by Month

Devotional or liturgical manuscripts often feature calendars that provide a wealth of information about faith and the cosmos. One such codex type, the book of hours, contains prayers and readings for daily to annual use. A calendar for the month of May in a mid-15th-century book of hours from Paris, for example, begins with an inscription stating that May has 31 days and 30 appearances of the moon. The first column includes Roman numerals to help readers determine the phases of the moon. They used this information to make decisions, such as when to fast or seek medicinal remedies. The second column indicates the days of the week, lettered A through G. At the bottom of the page, the artist included the so-called Labor of the Month, a seasonally appropriate activity such as picking flowers in April or sowing a field in October. Each sign of the zodiac was assigned to a full month during the Middle Ages, whereas today’s astrology follows a slightly different dating system.

A diagram from a 1518 calendar manuscript indicates 54 major veins that may be drained according to the phases of the moon or the season of the year. This practice of bloodletting, an ancient medical process of withdrawing blood, seeks to balance bodily fluids known as humors (such as black and yellow bile and phlegm).

The figure depicted also contains zodiac symbols, each one holding power over a particular body part: Aries (♈) on the head; Taurus (♉) on the neck; Gemini (♊) on the shoulders; Cancer (♋) on the chest; Leo (♌) on the sternum; Virgo (♍) on the stomach; Libra (♎) on the lower abdomen; Scorpio (♏) on the genitalia; Sagittarius (♐) on the thighs; Capricorn (♑) on the knees; Aquarius (♒) on the legs; and Pisces (♓) on the feet. The most famous medieval representation of the Zodiacal Man appears in the French manuscript known as the Très Riches Heures de Jean de Berry, illustrated by the Limbourg Brothers.

Visions of the Universe in the Christian Tradition

A selection of manuscripts in Wondrous Cosmos provides insights into Christian theology and celestial themes in sacred scripture and art. These include a music manuscript showing the creation of the world; the Book of Good Manners detailing the cosmic battle between warrior angels and rebel angels; and numerous episodes from Christ’s life (the angelic annunciation of Jesus’s birth to shepherds, the magi following a star to find the Christ child, the eclipse during the Crucifixion, and Christ’s ascension into heaven). The images and accompanying texts demonstrate the central role of heavenly lights, angels, and demons in church services and private devotional practices.

A centerpiece of the exhibition is the Getty Apocalypse, a mid-13th-century English manuscript containing the biblical book of Revelation (also called Apocalypse), which describes enigmatic visions of the end of time. One of the most stunning page spreads features the so-called Woman Clothed in the Sun, with the moon at her feet, stars in her hair, and sunlight wreathing her body. The commentary tells us that the woman represents the Church, which gives light to both day and night. She gives birth to souls saved by angels, while a dragon, representing the devil, gathers one-third of the stars of the heavens in its tail, a symbol of Apocalypse.

Out of this World Connections Across the Globe

Several manuscripts and printed books in the exhibition reveal the global entanglements of astronomical or astrological ideas during the Middle Ages. For example, two miscellanies at the Getty contain constellation diagrams with the names of star groupings sometimes provided in Latin, Greek, and Latinized Arabic. This linguistic diversity confirms the connections among universities in Western Europe and centers of learning in Eastern Europe, Western Asia, and the vast Muslim world, where texts in many languages were copied, translated, and transmitted.

The tale of Barlaam and Josaphat by Rudolf von Ems, from about 1200 to 1254, illustrates cosmic themes through a story in India. At the beginning of the tale, the imaginary King Avenir of India consults astrologists to interpret omens of planetary and astral alignment related to the birth of the future prince Josaphat. They predict that the young prince will convert to Christianity, which angers the king, who then confines his son to the palace. Inspired by encounters with sickness, poverty, old age, and death, the prince still becomes Christian, fulfilling the celestial prophecies. The saying “written in the stars” expresses the belief that cosmic or universal forces control the future, a theme found in this story as well as works of history, literature, and oral tradition around the world since time immemorial.

The architecture of sacred structures built or enlarged during the medieval period and sites of pilgrimage also often evoked ideas of the cosmos and the place of humans within it. A major pilgrimage site in India, the Great Stupa at Sanchi, offered Buddhists a metaphorical microcosm of the universe. For Muslims, the Dome of the Rock in Jerusalem commemorates the Night Journey, when the angel Jibril (Gabriel) transported the Prophet Muhammad from Mecca to Jerusalem and into Heaven. Meanwhile, sculptors adorned the façade of Amiens Cathedral in France with the Virgin and Child and saints, making it a heavenly portal into the church space.

Art and Wonder Across Time

I have always been fascinated by the celestial realm. This exhibition is inspired by a range of sources in my life, including my childhood spent stargazing on camping trips and watching Star Trek and Star Wars. Carl Sagan’s Cosmos: A Personal Voyage is a long-time favorite (as is Neil deGrasse Tyson’s edition).

More recently, I’ve become fascinated by an event that captured the attention of people worldwide many centuries ago. In 1054, people witnessed the light burst of what is now known as the Crab Nebula, a supernova. Contemporaneous texts describing the fantastic cosmic event exist in Japan and Iraq; later references to the awesome astral phenomenon can be detected in China and Central Europe. Pictographs, carvings, rock art, and cave paintings found across North America may also memorialize the sighting.

Clearly an interest in the cosmos has a long history, and there is still so much to learn about our shared global past. Archeoastronomers and archivists continue to piece these clues together, drawing connections between distant communities, the medieval world, and our own time. I hope visitors to the exhibition will take a moment to pause from the business of life to ponder these connections, inspired by medieval illustrations about the cosmos.

This show is dedicated to you, mom and dad.

This essay first appeared in the iris (CC BY 4.0).