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Excavating Early Archaeology: Preserving the Calendar Stone

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Preservation is the suspension of an object between life and death.                                                                               Rem Koolhaas, Preservation is Overtaking Us

The earliest history of the archaeology and the re-discovery of the monuments of the Aztec and the Maya in the Americas is a truly fascinating, and highly problematic subject. Linked to the European and Spanish colonization and exploitation of the indigenous peoples of the Americas, many who participated in uncovering the earliest remains of past cultures also worried about the preservation of these important objects for the future.

One of most original early texts in this vein found in the Jay I. Kislak Collection of the Library of Congress, is the Descripción histórica y cronológica de las dos piedras que con ocasión del nuevo empedrado que se está formando en la plaza principal de México, se hallaron en ella el año de 1790 [ A Historical and Chronological Description of Two Stones, which were found in 1790, in the principal square of Mexico during the current paving]. Written by Antonio de León y Gama and published in 1792, it is considered by many scholars and historians to be the founding document of antiquarian studies in the Americas.

The book illustrates one of the earliest and most important discoveries in the archaeology of Mexico, the Aztec Calendar Stone. The stone, found in the Zócalo, or the main plaza of Mexico City on December 17, 1790, is a huge basalt slab, weighing more than twenty-four tons, and measuring eleven feet and five inches in diameter. Besides the Sun stone, as noted in the book title, the text also chronicles the unearthing of a second sculpture, a representation of Aztec goddess Coatlicue.

Engraving of the Calendar Stone from León y Gama’s Description, published 1792. Kislak Collection, Library of Congress

The drawings and copper-plate engravings of the stone and sculpture were done by Francisco de Agüera, one of a group of engravers working in Mexico City during the late eighteenth century, whose work was mostly dedicated to devotional scenes and the illustrating of saint’s lives.

The image of the Calendar Stone will be familiar to many readers and is one of the best known images illustrating the archaeology of the early Americas. The middle of the stone shows the face of the sun god holding a human heart in the claws emanating from the center. The four squares surrounding the deity are representations of previous ages illustrated by a jaguar, water, wind, and rain. Thought to have been carved sometime between 1250 and 1521 of basalt from the Xitle volcano, it was found, as the full title of the book suggests, during the laying of new paving stones near the cathedral, in December of 1790.

León y Gama’s description of the events surrounding the finds are very much the same as many discoveries in the history of archaeology–the results of a construction project.

The government having given orders to level and pave the great square, and to form works to conduct waters through subterranean canals; they met whilst digging for this purpose, at a small depth from the surface of the earth, with a curiously worked statue of hard stone and of extraordinary size […]. A few months passed when they found another stone [calendar or sun stone], much larger than the first.

The Coatlicue sculpture, dramatically represented by León y Gama in the engraving, is the Aztec goddess credited with giving birth to the moon, the stars, and other gods denoting the sun and war. The goddess is normally represented, as she is in this sculpture, wearing a skirt or dress made of snakes and a necklace of human hearts.

Engraving of the sculpture of Coatlicue. Kislak Collection, Library of Congress.

Included in the Library’s copy of the book are three watercolors, inserted as studies of the Nahuatl calendar and directional glyphs. These are represented on concentric rings on the sunstone showing twenty days and eighteen months. The sequence begins in the top center and goes counterclockwise with pictographs for crocodile, wind, house, lizard, serpent, skull/death, deer, rabbit, water, dog, monkey, herb, cane, jaguar, eagle, vulture, movement, flint, rain, and flower, representing the twenty months of the calendar.

One of Three Manuscript Inserts of the Nahuatl calendar into the Kislak copy. Kislak Collection, Library of Congress

Antonio de León y Gama was completely taken with the finds and was concerned for the preservation both of the objects themselves and the history of the native peoples of Mexico that they represented. He writes that,

Being exposed to the public, there was no preventing rustic and childish people from injuring several of its figures with stones and other implements, this in addition to the damage they suffered in raising them. Before they should do more damage, or its destiny changed […]; I caused an exact copy of it to be drawn in my presence; to keep it in my power, as an original monument of antiquity.

León y Gama was inspired both by the amazing artistry of the sculptures but also by the fact that the discoveries confirmed his belief that the works of the ancient Americas would rival any other culture. He writes that he was, “determined to publish the description of both stones, in order to throw some light on ancient literature, so much encouraged in other countries.” What inspired him was the recent museum founded in Portici, Italy, created by the King of Naples, to show off the treasures from excavations in Herculaneum and Pompeii, “buried for so many years under the ashes, stones, and lava thrown out by the eruptions of Vesuvius.”

It is one of the most thoughtful publications in the long history of the early archaeology of the Americas and one that paved the way for its preservation.


  1. My comment is unrelated to this specific blog post. I read in the Washington Post that you were collecting examples of data visualizations related to the pandemic. I am a journalistically-trained graphic artist, and as you might expect I have crafted many graphics about the progress of the pandemic since this thing began, tracking it globally and in the United States. If you might be interested, I could send you jpegs of what I think the best ones turned out to be, but I don’t know how to contact you. They’re traditional static graphics – not interactive, but carefully designed. Best regards, and I shall check in on your blog. – R. Dorrell

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