Initial Conditions Episode 11: The Legacy of Ptolemy's Almagest

Initial Conditions Episode 11: The Legacy of Ptolemy's Almagest

The images, texts, and details that did not make it into this week’s episode of Initial Conditions: A Physics History Podcast

Find the corresponding podcast episode here: Initial Conditions - A Physics History Podcast

Things that get better with age:

  • Wine
  • Chris Pine
  • Taylor Swift’s discography

Things that do not get better with age:

  • Milk
  • Produce from Trader Joes
  • My ability to watch a sporting event from start to finish

Naturally, when I was researching the Almagest, the oldest manuscript in the Wenner Collection (printed in 1528 but originally written in 150 CE), I asked myself, “did the Almagest get better with age?”

The inside cover of the Niels Bohr Library & Archives’ copy of the Almagest

The inside cover of the Niels Bohr Library & Archives’ copy of the Almagest. Without knowing Latin, you can make out the name of the author, Claudius Ptolemy, and the name of the translator, George of Trebizond. You can also glean it was printed in Venice and, with a little research, from the distinctive “L A” and fleur-de-lis, discern the Giunti Press is behind this print. 

Claudius Ptolemy lived around 100-170CE in or near Alexandria, Egypt. He is known for his many influential works including Mathematike Syntaxis (also known as the Almagest), Geographia (also known as the Cosmographia), and the Tetrabiblos (also known as the Quadripartitum). In this body of work, Ptolemy mathematically explains mechanisms of the universe and applies them to create a usable framework to understand the world, the stars, and the stars’ impact on the world. The Almagest was one of the most influential texts in astronomy from its publication through the 15th century. Today, however, we know some of Ptolemy’s mechanisms were faulty (the geocentric model of the solar system was disproved in the 16th century), some of his applications are no longer accepted as science (specifically, the use of astrology), and even the authenticity of some of his astronomical observations have come into question. So, did the Almagest age like an early 2000s sitcom with misogynistic undertones? I argue that the astronomy, mathematics, and greater understanding of the world facilitated by the Almagest preserved its legacy.

Aristotle, Ptolemy, and Copernicus

Depicted left to right are: Aristotle, Ptolemy, and Copernicus. Original frontispiece from Galileo's Dialogues on the Great World Systems

Media Credit: AIP Emilio Segrè Visual Archives, Catalog ID: Galileo Galilei H4

For its time, the Almagest was perhaps the greatest astronomical text ever written. Its adopted name, Almagest, is actually a translation and slang-like evolution of “the greatest collection.” Al comes from the definite article in Arabic and magest derives from, megístē, Ancient Greek for “greatest.” In many ways, the evolution of the text’s name is representative of the evolution of the text itself. Ptolemy wrote it in Greek and was heavily influenced by classical Greek philosophy and past Greek and Babylonian astronomers. In the text, he compiled and streamlined what was known about astronomy and math into one document. He also included a comprehensive star table and a model that simulates the motion of celestial objects. 

Ptolemy proposed a geocentric model, or a model of the solar system where all the planets and celestial objects orbit Earth. About four hundred years before Ptolemy wrote the Almagest, Aristotle observed that objects fall towards Earth and deduced that everything must fall toward the center of Earth and therefore that Earth must be at the center. Greek philosophy emphasized the importance of circles and Aristotle concluded that the rising and setting of planets was because they orbit Earth in circles. Aristotle took it a step further and inferred that each planet was resting on a sphere nested in a set of planet-carrying spheres, like Russian nesting dolls (but way bigger). The spheres that carry the planet rotated and that motion, said Aristotle, is why planets rotate. Beyond the planetary sphere, Aristotle imagined, was the celestial sphere where all the stars outside our solar system lay. 

Ptolemy inherited Aristotle's vision of the solar system but his observations on the motion of the planets were difficult to reconcile. It appeared as though sometimes the planets would move backward in the sky. The backward motion is called retrograde motion and is produced by Earth’s relative motion to the planet. But Ptolemy, who assumed the planets orbited Earth, proposed a different solution: epicycles. Epicycles are little circular orbits placed along the route of a planet's larger, circular orbit that would result in apparent retrograde motion. Like fixing a car with duct tape, the epicycles did not address the real issue with Ptolemy’s model so he had to keep adding epicycles creating a very complex model. Yet, the model functioned for a long time with this duct tape solution.

Diagram of Ptolemy's model of the solar system

Ptolemy’s model of the solar system with Earth at the center of rotating spheres that determine planets’ orbits. He added epicycles to account for the confusing, backward motion of the planets caused because Earth and all the other planets actually orbit the Sun. 

You can read more about Greek philosophy and Ptolemy in this web exhibit and more about the geocentric model and epicycles in this web exhibit from the Center for History of Physics.

During the rise and spread of Islam in the 7th century, the Almagest was adopted and critiqued by Arabic astronomers. Some of the most prominent scholars to interact with Ptolemy’s work were Al-Ḥajjāj ibn Maṭar in the 9th century, Nasir al-Din al-Tusi in the 13th century, and Shams al-Din al-Khafri in the 16th century. They built upon Ptolemy’s model and made more precise observations that hold to this day. 

In Europe, during the 16th century, there was a resurgence of Classical Greek philosophy. Coupled with new technologies such as the printing press and the telescope, Ptolemy’s work was repopularized and evaluated. Famously, Nicolaus Copernicus proposed a heliocentric model of the solar system which Galileo Galilei, aided by his telescope, defended. Eventually, the world moved on from the model Claudius Ptolemy proposed in the second century.

The Almagest’s impressive, fourteen hundred year legacy, from the second century to the sixteenth, provides insight into how the production and pursuit of knowledge changed throughout history. In many ways, the story of the Almagest is the story of astronomy. This episode dives into the history of the text and the importance of the Arabic astronomers in building the field of astronomy. 

This blog post, in my mind, is titled “Episode 11: Cut for Time,” and is similar to the bloopers at the end of Toy Story (a film that ages like a good whiskey: it gets better with time, but also more likely to make me cry). This is the story of the Giunti Printing Press that produced the copy of the Almagest that made its way from Renaissance Venice, Italy to our library in College Park, Maryland. An International Renaissance Publishing Family: The Giunti by William A. Pettas follows the international dominance of this powerful printing family. It reads like an early version of Succession, or reminds me of other, prominent business dynasties…

The world changed with the invention of the printing press. Johannes Gutenburg invented the moveable type printing press in 1440 and the technology quickly spread across Europe. There was a flurry of printing excitement, especially in Venice, as the materials for printing were fairly inexpensive. However, book supply soon outpaced demand as it was most cost effective to print multiple copies at one and many printers went out of business. It took a shrewd, opportunistic business mind to thrive in such an environment. Lucantonio Giunti possessed such a mind. 

In 1477, around age 22, Lucantonio Giunti left his six brothers and wool-merchant father to join the flourishing stationary trade in Venice. Following his brother’s example, Filippo Giunti, who had once worked for a well known artist, opened his own stationary shop in Florence. Soon, the two brothers vertically integrated their respective operations, from merely selling books and paper products to producing the books themselves. By 1489, Lucantonio had become successful enough to publish in his own name, producing profitable religious texts often in large formats that were illustrated and complemented with red ink. While many printers struggled to find demand for their work, the Church proved to be a faithful patron to Lucantonio.

In Florence, Filippo did not find the same overwhelming success as Lucantonio. In 1491, Lucantonio proposed a deal to his brother that promised both of them profits. They combined all their assets (everything from their store’s inventories to their wives’ dowries) and created an international partnership between both firms. This pool of money totaled 4,500 florins, equally donated by both brothers, who could use the money  as needed for five years to support their families and operations. At the end of the five years, Lucantonio would take seventy-five percent of the resulting profits and Filippo would take the other quarter. Filippo’s position in Florence, printing mainly humanistic works, was less favorable than Lucantonio’s in Venice and he benefited from the wider reach provided by their international partnership. In the end, their shared pot of money amounted to 11,032 florins after living expenses were deducted. This deal was advantageous to both Giunti brothers and they renewed the contract under the same terms. This time, the deal was to last 10 years.

Not finding much success printing Greek works in Florence, Filippo changed tactics. In 1503, his firm pivoted to a compact format of Latin classics facilitated by a new cursive typeface. This was a blatant imitation of the printer Aldus Manutius’s iconic style and patented design. Not only that, but Filippo’s firm began a habit of using the same texts at Manutius. Questionable ethics aside, the Giunti brother’s partnership came to an end in 1510, but it took seven years and an intervention by their nephew, Giuntino, to arbitrate the profits. The disagreement arose because though their combined profits continued to grow, Filippo’s assets remained the same. Eventually it was decided that Lucantonio must pay Filippo the 3,451 florins he was owed. The payment was not entirely in cash; some of the debt was paid in paper, some in printed books. Filippo died in Florence, September 1517, shortly after settling the financial dispute with Lucantonio.

After proving his business savvy to Lucantonio, Giuntino managed a publishing partnership on behalf of his uncle and even entered into a similar business arrangement to the one he had helped mediate. Giuntino was not the only nephew to join the family business. By the 16th century, it appears his brother, Iacamo, expanded the family’s trade into Rome, facilitating a greater reach for Lucantonio’s publications. The third brother of this younger Giunti generation, Giovanni, stayed behind in Florence, managing Lucantonio’s non-printing related estates. 

Giunti Family Tree

Giunti Family Tree

Media Credit: William A. Pettas


The family business continued to grow. Lucantonio’s nephew, Giacamo, made a deal with Lucantonio to borrow 2,000 florins to expand the book trade in the burgeoning cultural center of Lyon. By 1520, Giacamo joined local publishing partnerships which themselves contained a complicated web of connections and politics. Giacamo found success in printing liturgical, medical, and theological works in Latin in expensive folio format. His works were more bare bones than his uncle’s elaborate texts but were cheaper to produce and suited the clientele in Lyons. Interestingly, unlike most printers, he outsourced his printing works instead of hiring his own printing crew. Between Giacamo’s far reaching family ties and his local partnerships, he had eliminated competition and was earning unprecedented amounts of money in printing, which funded future endeavors. 

When both Giovanni’s brothers, Giuntino and Iacamo, passed away in the 1520’s, Giovanni inherited their businesses and appointed another member of the family, his cousin, Giacamo’s brother Benedetto, to supervise Giunti’s operations in Rome. Benedetto became a tremendous success, partnering with some of the largest names in printing and signing an exclusive deal with the Vatican in 1536. Prosperity in Rome was short-lived, however, and it seems the business had failed by 1551.  

Settling Giuntino’s affairs was a little more complicated than Iacamo’s. The deal Giuntino made with Lucantonio was incredibly profitable, even after Giuntino’s untimely death. Giovanni maintained Giuntino’s affairs on behalf of Giuntino’s heirs and, in an arbitration in 1535, claimed the heirs should inherit the profits according to the deal. Lucantonio, never sentimental for his family, claimed the deal was null when Guintino died. Giovanni likely was interested in the large sum of money Giuntino was due and even filed claims against other facets of Lucantonio’s operation. 

Succession dynamics aside, this printing dynasty eventually spanned multiple cities, generations, and genres of texts. The Venetian operations prioritized classical and religious texts while other cities aimed at more popular audiences. Particularly in Florence, where there was tremendous national pride, the Giunti operation printed a majority of their work in the local vernacular which was uncommon for European printing presses. Their distinctive printing mark, the fleur de lis, is an overt nod to their Florentine roots. Regardless of city (or duchy), the Giuntis were a printing institution.

Discorso Al Serenissimo Don Cosimo II by Galileo

Discorso Al Serenissimo Don Cosimo II by Galileo printed by Filippo's great grandson, Cosimo Giunti, in 1612. This text demonstrates the longevity and reach of the Giunti family.

Media Credit: Library of Congress, Rare Book and Special Collections Division

So, it is perhaps unsurprising that the copy of the Almagest held by the Niels Bohr Library & Archives was printed by the Giunti Press in 1528. Given its content, a classical Greek text featuring Aristotelian philosophy and a geocentric model of the heavens, it would have been an obvious choice for Lucantonio to print. And I, for one, am grateful that he did. 

If you want to learn about how the Almagest aged and was read, critiqued, and modified throughout the centuries, listen to this week’s episode of Initial Conditions and you can decide for yourself if you believe the ancient text has aged like Anne Hathaway (who simply does not age). 

The Greek Worldview.” A Cosmic Journey: A History of Scientific Cosmology. Center for History of Physics. Accessed August 30, 2022. 

Pederson, Olaf. A Survey of the Almagest With Annotation and New Commentary by Alexander Jones. Edited by Alexander Jones. Springer: New York, New York, 2010.

Saliba, George. “A Sixteenth-Century Arabic Critique of Ptolemaic Astronomy: The Work of Shams Al-Din Al-Khafri.” Journal for the History of Astronomy 25, no. 1 (1994): 15–38.

Seale, Natalie Lussey. “The Culture of Venetian Print.” Facendo Il Libro. The New York Academy of Medicine. Accessed August 31, 2022.

William A. Pettas. “An International Renaissance Publishing Family: The Giunti.” The Library Quarterly: Information, Community, Policy 44, no. 4 (1974): 334–49.


About the Author

Maura Shapiro

Mars Rover

Maura Shapiro

Maura Shapiro was a Podcast and Outreach Coordinator for the Niels Bohr Library & Archives'  Initial Conditions: a Physics History Podcast (to be released Summer 2022) and has since moved on to other roles within AIP. She interned with the Niels Bohr Library & Archives and Center for History of Physics in the summer of 2021. She earned degrees in both Physics and Communication & Rhetoric from the University of Pittsburgh and loves hiking, biking, and almost anything outdoors! 

Caption: An artist's concept of NASA Mars Exploration Rover Opportunity, one half of the twin rover mission, on the surface of Mars. Opportunity diligently worked for almost fifteen years, surpassing its 90 sol (martian day) lifespan by 5,262 sols or almost 6,000 percent.

See all articles by Maura Shapiro

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