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Heaven and Earth in Ancient Mexico

Heaven and Earth in Ancient Mexico
Astronomy and Seasonal Cycles in the Codex Borgia

Offering a major new interpretation of the enigmatic middle section of the Codex Borgia, Milbrath demonstrates that this ancient painted text is the most important historical record of pre-Columbian astronomy and natural history in central Mexico.

Series: The Linda Schele Endowment in Maya and Pre-Columbian Studies

January 2013
This book is out of print and no longer available.
224 pages | 8.5 x 11 | 101 color and b&w illus., 19 tables |

The Codex Borgia, a masterpiece that predates the Spanish conquest of central Mexico, records almanacs used in divination and astronomy. Within its beautifully painted screenfold pages is a section (pages 29–46) that shows a sequence of enigmatic pictures that have been the subject of debate for more than a century. Bringing insights from ethnohistory, anthropology, art history, and archaeoastronomy to bear on this passage, Susan Milbrath presents a convincing new interpretation of Borgia 29–46 as a narrative of noteworthy astronomical events that occurred over the course of the year AD 1495–1496, set in the context of the central Mexican festival calendar.

In contrast to scholars who have interpreted Borgia 29–46 as a mythic history of the heavens and the earth, Milbrath demonstrates that the narrative documents ancient Mesoamericans’ understanding of real-time astronomy and natural history. Interpreting the screenfold’s complex symbols in light of known astronomical events, she finds that Borgia 29–46 records such phenomena as a total solar eclipse in August 1496, a November meteor shower, a comet first sighted in February 1496, and the changing phases of Venus and Mercury. She also shows how the narrative is organized according to the eighteen-month festival calendar and how seasonal cycles in nature are represented in its imagery. This new understanding of the content and purpose of the Codex Borgia reveals this long-misunderstood narrative as the most important historical record of central Mexican astronomy on the eve of the Spanish conquest.

  • List of Illustrations and Tables
  • Preface
  • 1. Context and Calendars in the Codex Borgia
  • 2. Seasonal Veintena Festivals in Central Mexico
  • 3. The Sun, the Moon, and Eclipses in the Borgia Group
  • 4. Planetary Events in the Codex Borgia
  • 5. Astronomy and Natural History in the Codex Borgia
  • Notes
  • Glossary
  • Bibliography
  • Index

Susan Milbrath is Curator of Latin American Art and Archaeology at the Florida Museum of Natural History and Affiliate Professor of Anthropology at the University of Florida. She also authored Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars.


The Codex Borgia, a Precolumbian masterpiece that predates the Spanish conquest of Central Mexico in 1521, records almanacs used in divination and astronomy and is a unique section with an astronomical narrative. Comparative studies of surviving codices from Central Mexico have helped identify seasonal ceremonies and natural history events in the narrative, and computer planetarium programs and other tools for the study of archaeoastronomy have also proved invaluable. The intriguing paintings on Borgia 29–46 provide detailed records that are comparable to Maya codices in terms of natural history content, but the Borgia artists conveyed this information using a rich palette of symbols rather than glyphic texts.


The 76-page Codex Borgia unfolds like an accordion painted on the front and the back, on a ground of lime-coated deerskin that displays colorful cartoonlike images outlined in black. Pages 29—46 depict an enigmatic narrative that has been studied for more than a century, but has remained a puzzle. This book proposes a new interpretation that emphasizes natural history, synthesizing data from the fields of ethnohistory, anthropology, art history, and archaeoastronomy to explore these complex images. After more than two decades of study, I believe that I can demonstrate that the events portrayed on Borgia 29—46 are an astronomical narrative detailing noteworthy events over the course of a year in the context of the Central Mexican festival calendar.


Evidence for interpreting the astronomical narrative on Borgia 29—46 is detailed in the following chapters, and the last chapter presents an overview, followed by annotated illustrations summarizing the main events portrayed in the annual cycle appear in Plates 1–18. By combining the study of iconography and astronomy, it is now possible to see this enigmatic narrative in a new light, allowing us to appreciate the integration of art and science characteristic of ancient Mesoamerica. The ability of artists in ancient Mexico to depict complex ideas using representational images means that glyphic writing was not an essential component for conveying astronomical knowledge. Using only pictures, the eighteen-page sequence represents the transformation of Venus from Evening Star to Morning Star and back to Evening Star once again, all taking place during the year 1496, only twenty-five years before the Spanish conquest of Mexico.


The Codex Borgia has intrigued me for more than twenty years, but my investigation of this fascinating screenfold book began on a circuitous route. My dissertation research focused on the art and archaeology of the early Mesoamerican Olmec civilization, dating over two thousand years before the Postclassic period (AD 900—1521), the time associated with the codices. My major professor, Esther Pasztory, offered a seminar on the codices at Columbia University, but I was in Latin America that semester. When it came time to take my PhD qualifying exam, I realized that I had indeed missed a great deal, because in preparing for the exam I had not studied the painted books of ancient Mexico. Near the end of my exam, Esther projected a page from a codex and asked me to interpret the imagery. I cannot remember the weak answer I struggled to provide, but I later learned I had failed to identify a scene from the astronomical narrative in the Codex Borgia. Even though I passed the exam, I could tell that Esther was disappointed. She later commented that a Precolumbian scholar failing to recognize the Codex Borgia was like a Renaissance scholar being unable to identify the Sistine Chapel.


Clearly, I could no longer ignore the codices. I began studying their rich iconography, starting with Aztec codices that had Spanish or Nahuatl (Aztec) writing or glosses to help identify the imagery. Around that time, I also became intrigued by the potential for linking my study of iconography to archaeoastronomy, an interdisciplinary field that developed in the late 1970s under the leadership of Anthony F. Aveni.


After receiving my PhD and teaching for a few years, I was awarded a postdoctoral fellowship by the Tinker Foundation to conduct research on the role of astronomy in the Aztec festival calendar, with Anthony Aveni and Michael Coe serving as my mentors. Although the Codex Borgia was not really part of this fellowship study, I began to recognize rituals in the Borgia narrative that had parallels with Aztec festivals. I also realized that astronomical imagery and seasonal cycles played an important role in the narrative. I began studying the work of Eduard Seler, whose German commentary on the Codex Borgia, published in 1904—1909, was widely accessible in a 1963 Spanish edition published in Mexico. Seler interpreted Codex Borgia 29—46 as an astronomical narrative of an Orpheus-like descent into the underworld, featuring Quetzalcoatl as the embodiment of the planet Venus.


His interpretation had a certain appeal, but it failed to account for apparent parallels with Aztec seasonal ceremonies. Furthermore, beginning in the mid-1960s, European scholars began to discredit Seler's work. In a 1978 review of his three-volume commentary, Maarten Jansen championed the criticism, relegating Seler's work to the realm of "astral theories" that were obsolete. Despite this critique and the clear evidence that Seler forced his interpretations beyond reasonable bounds, I was convinced that he was right in emphasizing the importance of astronomy in Borgia 29—46, for the pages are filled with images of stars, sky bands, solar disks, and Venus gods.


Investigating further, I realized that Karl Nowotny's 1976 commentary on the codex had failed to identify some key images linked to the Aztec festival calendar and concluded that the eighteen-page astronomical narrative was divided into 20-day periods, like those represented by the eighteen festivals in the Aztec calendar. I presented my findings at a stimulating symposium at the University of Colorado, organized by Davíd Carrasco, who published the papers in an edited volume. In that 1989 chapter, I also developed a hypothesis that Venus events were represented over the course of a single year, with the annual festival calendar serving as a chronological framework. I also argued that Seler had made a significant error in his analysis of the Venus cycle: he had identified the first page of the sequence as an image of the disappearance of the Morning Star, when it instead represented the disappearance of the Evening Star.


A number of events shaped the direction of my subsequent research. The 1992 discovery at Ocotelolco, Tlaxcala, of a mural very similar to Codex Borgia 32 proved that the Codex Borgia was from the Puebla-Tlaxcala Valley and that it dated relatively late, in accordance with the fifteenth-century date of the murals. Another important development was a 1986 article in Mexicon on the Dresden Codex published by Victoria and Harvey Bricker, which explored real-time astronomical events in the Maya almanacs. Anthony Aveni applied a similar model to the Codex Borgia in a 1999 article in which he identified fifteenth-century dates that coincided with specific astronomical events. This real-time model was later expanded in a 2001 article on the Borgia by Victoria Bricker. As it turned out, almanacs on pages 27—28 helped me date the astronomical narrative that follows.


The eighteen-month festival calendar remained a valid organizing principle for the astronomical narrative with twenty days for each of the eighteen pages, but details of my 1989 study needed revision in light of the new data. I made a breakthrough when I identified the solar disks on page 40 as eclipse symbols, resembling Aztec eclipse images with a "pie wedge" cut out of the sun (CP 8).


This proved to be a key insight because it allowed me to test the placement of the festival calendar cycle. By studying all the eclipses visible in Central Mexico between 1325 and 1521, I determined that page 40 represents a total solar eclipse in 1496. This year correlates with significant Venus events occurring at key positions in the seasonal cycle. Realigning the sequence indicates that it begins on page 29, with the disappearance of the Evening Star on January 3 in the festival of Atemoztli, just after the winter solstice. The sequence ends on page 46 in Panquetzaliztli, with the newly emerged Evening Star in November, followed by the winter solstice.


I presented this revised interpretation at a symposium honoring Anthony Aveni, who had not only drawn me into the field of archaeoastronomy, but who also had inspired my research on real-time astronomical events in the Codex Borgia. The chapters that follow developed out of my 2007 article in the volume dedicated to Aveni, but here I expand the scope to incorporate seasonal imagery in the codex and the relationship to Postclassic festival calendars from Central Mexico.


To lay the foundation, Chapter 1 examines the historical context of the Codex Borgia and calendar dates and presents a synopsis of the seasonal cycles and astronomical narrative. Chapter 2 focuses on the Aztec festival calendar and corresponding images of specific festivals in the Borgia narrative. Chapter 3 investigates a dramatic eclipse event in August 1496 represented on Borgia 40 and its relationship to eclipses depicted in Aztec sources. This chapter also identifies other dates related to solar and lunar events and analyzes the solar and lunar deities represented in the astronomical narrative and in other sections of the codex. Chapter 4 discusses various Venus almanacs and associated deities in the Borgia, focusing on imagery of Venus gods and other astronomical companions. Chapter 4 also identifies depictions of a November meteor shower and a comet sighted in 1496, as well as images of the Milky Way. Chapter 5 summarizes what can be learned from study of the astronomical narrative, emphasizing the importance of natural history in seasonal imagery and the integration of the Venus cycle with the solar cycle over a span of eight years.


I am indebted to the Tinker Foundation for funding my original research on the Aztec festival calendar and to Esther Pasztory for encouraging me to conduct that research. Anthony Aveni and Michael Coe provided guidance during the Tinker Postdoctoral Fellowship, and both continue to inspire me with their creative thinking and cogent writing. My long-standing interchange with Aveni has been an enduring part of my development as a scholar, and the many international conferences he has been involved in have provided me access to the latest research, stimulating my development as a scholar. Another international conference at the Vatican Observatory in 1994, organized by Raymond White and Rolf Sinclair, allowed me, with the help of Father Leonard Boyle, special access to the Codex Borgia in the Vatican Library. Research conducted in 2000 with funding from the Foundation for the Advancement of Mesoamerican Studies Inc., contributed to both Chapters 3 and 4, and a sabbatical leave granted by the University of Florida in 2006 allowed me to make further progress on the Codex Borgia research.


I appreciate the help provided by a number of people in developing this book. At the symposium at Colgate University honoring Anthony Aveni, I received much-needed comments on my new interpretation of the Borgia, and careful editing of my paper by Gary Urton and Clive Ruggles, the conference organizers, greatly improved the paper in their volume, published in 2007. During that symposium and thereafter, Ed Krupp, director of the Griffith Observatory in Los Angeles, shared insights about naked-eye astronomy that helped me understand why Venus is so prominent in eclipse imagery. Harvey and Victoria Bricker have always been generous with their time and have inspired my work in countless ways over the years. I also want to thank Harvey for guidance on astronomy and Vicki for reading and commenting on selected chapters of this book. Aveni served as a reviewer of the original manuscript after submission to the University of Texas Press and gave me excellent suggestions on how to improve the text. Anne Cassidy kindly sent me a copy of her 2004 dissertation on the Borgia Group codices and served as reviewer of the manuscript after submission, providing sage advice about how to make the interpretations more accessible. My husband, Mark, and my sister, Connie, contributed much-needed editorial assistance. Also, my thanks to Kathy Bork for editing the final manuscript and to Theresa May of the University of Texas Press, who guided me through the publication of Star Gods of the Maya in 1999 and has now given me another opportunity to publish with the press.


The annotated plates at the end of the book were created by scanning a color reconstruction of the Codex Borgia painted by Gisele Díaz and Alan Rodgers, and permission to use the visuals was granted by Bruce E. Byland, author of the 1993 commentary published in the Dover edition. Ian Breheny created these synopsis images and all the color plates for this book, redrawing the photos from the photographic facsimile edition published by Akademische Druck- und Verlagsanstalt and restoring some lines and colored areas that were effaced. Drawings originally commissioned for Seler's publications served as the basis for most of the line drawings, and these were cross-referenced for accuracy with photos of the actual codex. The Sky Maps in Chapter 4 were developed by Jeffrey Vadala using Stellarium shareware and Google Earth mapping programs to help re-create the local horizon in Tlaxcala.


I am also grateful to Elizabeth Boone for sending the manuscript of her book, Cycles of Time and Meaning in the Mexican Books of Fate, which was published in 2007. Her careful analysis of the visual imagery in the Codex Borgia inspired a number of my interpretations. Boone's analysis of pages 29—46 as a narrative steeped in the legends of creation cosmology seems quite different from my approach, but my interpretation does have a cosmological component if you consider cosmology as a branch of astronomy that deals with the origin, structure, and space-time relationship of the universe. In the Codex Borgia, cosmological principles of time and space are central to the astronomical narrative.



“The Codex Borgia is one of the most important works of art to have survived the conquest of Mexico, and the enigmatic middle chapter that Milbrath is interpreting is the most beautiful and least understood part of the codex. There’s very little published about this chapter in any language, much less English. . . . Her argument that the middle chapter combines a record of a particular solar year’s astronomical events, human ritual events, and earthly natural history (weather, pests, crops) is a beautiful idea that might be correct. Even if it isn’t correct, it is worth thinking about because it throws a new light from a new angle on some old hoary theory. It throws a lot of other assumptions about the Codex Borgia into question, which is always exciting. It’s the synthesis and the overarching interpretation of that middle passage that make this book beautiful and valuable.”
Anne Cassidy, Associate Professor of Art History, Carthage College