Mount Tlaloc

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A walled court of stone stands open to the sky at more than four thousand meters, on a summit where for much of the year there is snow. It has no roof and never had one. From its threshold the whole basin falls away to the west, and on a clear morning the lake-cities that once filled the valley floor would have lain spread out below, small and far. The court was reached by a causeway of overlapping slabs that runs straight up the last of the slope, and it was built to be seen: whitewashed, its walls catching the light, visible — one old account says — from many leagues away. This is the shrine on the mountain the Aztecs called by the name of the rain-god himself.

The mountain and the god

Mount Tlaloc, Cerro Tláloc on the modern maps, is an eroded volcano on the eastern rim of the Valley of Mexico, in what is now the State of Mexico, rising to roughly 4,120 meters — by some measures 4,158 — which makes it among the highest summits in the country and one of the great peaks that ring the basin and gather its clouds. Its name is the god’s name. To the Nahua peoples of the valley the high mountains were not inert geology; they were the storehouses of water, the places where the rain was kept before it fell, and this one was held to be a chief dwelling of Tlaloc, the god of rain and lightning and the green growth of things.

According to the World History Encyclopedia, Tlaloc was reckoned among the most formidable powers of the Aztec world, a giver of the life-bringing rain and, when he withheld it or sent it as storm and hail, a destroyer. He did not work alone. The rain was carried and poured by the tlaloque, lesser rain-spirits who lived in the mountains and the clouds and kept the waters in great vessels, releasing them — gently or in ruin — over the maize. Beyond the rain lay his paradise, Tlalocan, the place of the green and the unending spring, where those who died by water and by lightning were received. The mountain was, in the plainest sense the religion knew, an entrance to that world: the rain petitioned not at a distance but at the source, in the high place where the clouds caught and the water was made.

The summit court answers this directly. Within its walls archaeologists recorded five rock formations — one at the center and one at each of the four corners — and these are read as the tlaloque, the four rain-bearers of the quarters and the god at the heart of them, with the cardinal scheme of Nahua cosmology laid out in stone on the roof of the world. On one side stood a structure that had held an image of Tlaloc and other figures. The same arrangement is painted in the surviving books. In the Codex Borgia, a screenfold of the pre-conquest religious tradition, a page given to the rain-god shows him five times over — at the four directions and the center — each figure pouring water from a vessel down onto a field of corn, the four kinds of rain distinguished by color and direction, some nourishing and some bringing blight. The court on the mountain is that page built at full scale and set where the rain begins.

The choice of the high peak was not arbitrary, and it was not unique to this one summit. Across the basin the mountains were ranked among the most charged of all sacred places — Popocatepetl and Iztaccihuatl to the south, the lesser peaks of the eastern and western rims, each held to keep its own water and its own weather. The rain came down from them; the springs rose at their feet; the clouds first gathered on them in the season of the rains. To go up a mountain was to go toward the source of the thing being asked for, and to enter, in the body, the region where the tlaloque did their work. Mount Tlaloc stood at the head of this order — the highest of the basin’s eastern peaks, bearing the god’s own name, crowned not with a natural shrine but with a built one. The other mountain-cults of the valley looked, in a sense, toward it.

Page 27 of the Codex Borgia: Tlaloc shown at the four directions and the center, pouring rain from vessels onto fields of maize. Pre-conquest central Mexican screenfold; public domain, via Wikimedia Commons.

The ascent of the rulers

The mountain held two seasons of rite, and they are not the same. The first, in the depth of the dry months, was the festival the Nahua reckoned as Atlcahualo, falling roughly from mid-February into the first days of March. The second, near the turning into the rains, was Huey Tozoztli, the Great Vigil, in spring. It is the second that gives Mount Tlaloc its singular place.

For most of the cults of the valley the offerings were made by priests, in the city, on behalf of the people. Huey Tozoztli on Mount Tlaloc was different. The rulers themselves climbed. According to the entries on the festival, the lords of Tenochtitlan and of the allied cities of the basin — the kings of the alliance that held the valley — made the ascent in person, a pilgrimage of rulers to the highest of all the altars, gathering first in the lowlands and then going up the long slope together to present their offerings and pray for the rain on which every harvest, and so the whole standing of the state, depended. The men who sat at the summit of the human order climbed to the summit of the land to ask, at the source, for water. The blue-and-white shrine of Tlaloc on the great pyramid of the capital, the Templo Mayor, stood for this mountain; once a year the rulers left the symbol in the city and went to the thing itself.

What was carried up and given there belonged to the same logic that ran through the whole of the religion. The world of the Aztecs was held to be the Fifth Sun, a fragile age that earlier suns had not survived — four prior worlds destroyed in turn by wind and water and fire and the falling of the sky — and the present one was kept in being only by an unceasing exchange between the people and the powers that fed and watered them. Nothing in this world was free. The sun moved because it was nourished; the rain fell because the debt for it was paid. The Nahua word for the obligation, nextlahualli, carries the sense of a payment due, a settling of accounts. What the powers gave was life, and what they were owed in return was, at the limit, life: a reciprocity exact and without sentiment, in which the most precious of substances flowed back to the source of the gift. To withhold the payment was to risk the order itself — the failure of the rain, the stopping of the sun, the end of the age. Tlaloc’s share of that debt, the sources record soberly, included the offering of children. In the dry-season rite of Atlcahualo, the colonial ethnographies report, young children were given to the rain-god on the sacred mountaintops, Cerro Tláloc among them, the children adorned in the manner of Tlaloc and the tlaloque and carried up on litters; and it was held that if they wept on the way, their tears were a sign of the abundant rains to come.

The fullest of these accounts is the work of the Franciscan Bernardino de Sahagún, whose great compilation from Nahua informants in the generation after the conquest preserves the order of the festivals — a record set down, it must be held in mind, under the Church and in the service of conversion, by men describing a world their mission was bent on ending. The rite is not in doubt; the lens it reaches us through is a colonial one, and the distance shows. The same paradox governs nearly everything that can be said about the cult: the witnesses who preserved it were the witnesses who were dismantling it, and what reaches us is the religion as recalled and reordered by those who had outlived its public life. Within the frame the informants were describing, the matter was simpler than the chroniclers’ horror allowed. The rain was real; the failure of the rain was death; the children were given so that the many should not starve. It was the costliest of offerings precisely because it was meant to answer the costliest of dangers, and the tears that were taken for a good sign were taken so because the whole transaction was about water — what the sky was being asked, at the source, to release.

The processional causeway of overlapping stone slabs ascending toward the summit shrine of Mount Tlaloc, Texcoco, State of Mexico. Photograph by Bodofzt, CC BY-SA 4.0, via Wikimedia Commons.

The mountain as instrument

The court did not only receive the rain-prayer; it measured the year that made the prayer due. Running up to the enclosure is a causeway of laid stone, on the order of 150 meters long, set on a precise bearing of about 101°55′ from north. That orientation is not toward the shrine alone. It points to the place on the horizon where the sun rises in the days around February 23 and 24 — close to the start of the rite-season and, in the Nahua reckoning, near a turning of the solar count. A procession moving up the causeway in those mornings would have walked toward the rising sun.

The archaeoastronomer Anthony Aveni and his colleagues, working through the late 1980s and into the early 1990s, read the summit complex as an instrument for the agricultural calendar — its alignments marking the sun’s horizon-positions at intervals of twenty days, the unit of the Nahua festival cycle, and tying Mount Tlaloc by lines of sight to other peaks where rites were kept on the days the sun stood over them. As the HeritageDaily summary of the work puts it, the ruins functioned as an observatory as well as a sanctuary, a place from which the dry-season’s end and the planting could be timed against the horizon. The petition for rain and the calendar of when to plant were one act on this mountain, performed at the same threshold, facing the same dawn.

The site’s history is longer than the empire that made it famous. The causeway has been dated to the centuries between roughly 350 and 900, deep in the era of the great valley civilizations, so that the Aztecs who climbed it in the fifteenth and early sixteenth centuries were inheriting and renewing a sanctuary far older than their own rise — a continuity of the mountain-cult that ran beneath the changing powers of the basin from the time of Teotihuacan onward.

The recovery

When the Spanish took the valley in 1521 the summit rites ended, and the court on the mountain fell out of memory into the snow and the wind. It was not destroyed; it was simply left. The site was mapped systematically in the 1950s, the rectangular enclosure and its causeway recorded, the surface still strewn with greenstone, potsherds, and obsidian — the residue of offering. As one of the highest archaeological sites in the Americas, it has drawn study less as a ruin to be cleared than as a structure to be read: surveyed, its alignments measured, its place in the agricultural and ceremonial calendar reconstructed from the stone and the sky together. The altitude has been both its preservation and its threat. The cold and the difficulty of the climb kept it from the looting and rebuilding that flattened so many lowland sites, but the soft pumice and tufa of which it is built weather quickly, and the damage recorded on the summit is read as the work of human visitors more than of the elements. A modern shrine raised near the old enclosure in the late twentieth century is a reminder that the peak never wholly lost its hold; pilgrims still go up.

The material of the cult it served has come up most fully not on the mountain but in the city below. The recovery of the Templo Mayor of Tenochtitlan, excavated from 1978, opened the buried offerings of the twin pyramid — and the Tlaloc side has yielded its own grim confirmation of the record. Among the deposits, Offering 48, found in the seasons of 1980 and 1981, held the remains of dozens of children — at least forty-two, mostly boys between roughly two and seven years old, laid in a careful arrangement — and the find is now read, as the Live Science account of the research describes, against the long and ruinous drought that struck the Basin of Mexico in the 1450s: a mass appeal to the rain-god in an age when the rain had failed. The archaeology establishes that the practice was real and that its scale could be large in a time of crisis. It does not bear out the figures the conquerors and their Tlaxcalan allies later reported, which served the politics of the conquest and have every mark of propaganda; the sober count comes out of the ground, not the chronicles.

What the city offering shows in stone and bone is the same reciprocity the mountain enacted in the open air. The shrine on the great pyramid was a model of the peak; the peak was the place where the god was met at the source. To stand at the summit court now — a roofless square of weathered pumice and tufa, its five stones set to the quarters, the causeway falling away toward the dawn horizon and the long-emptied lakebed beyond — is to stand where the highest powers of a world climbed as high as their land would let them, to ask the rain to come. A statue of the god, recovered and now in the National Museum of Anthropology in Mexico City, keeps the goggled eyes and the great teeth by which he was always known, the face of the power the rulers went up to address.

Stone image of Tlaloc with his characteristic goggled eyes and fanged mouth, Museo Nacional de Antropología, Mexico City. Photograph by Jaontiveros, CC BY-SA / GFDL, via Wikimedia Commons.

The valley below is now a city of more than twenty million, and the lake the kings looked down on is largely gone, drained over the centuries that followed the conquest. The mountain remains, and so does the court at its top, kept by the cold. Among the Nahuatl-speaking communities of central Mexico — a living people of well over a million today, not a vanished one — the high peaks are still addressed as bringers and keepers of rain, and offerings are still left in the mountains for the water. The particular rite of the kings does not survive. The intuition it was built on — that the rain is held in the high places, and that the people who depend on it owe something to the powers that keep it — is older than the empire and outlasted its fall.

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