Tlalticpac occupies the middle region of a much larger cosmos. Above the earthly surface extend the celestial regions, while beneath or beyond it lie the places associated with death and the interior of the earth. The best-known priestly arrangement describes thirteen heavens above Tlalticpac and nine regions of the underworld, each associated with particular gods, celestial bodies, colors, forces, or stages in the journey of the dead.
This arrangement is preserved most clearly in painted and written accounts produced during the early colonial period from Nahua traditions. The surviving descriptions are not entirely uniform, and the precise names or inhabitants assigned to individual regions sometimes differ. Even so, the division between the celestial world, the inhabited earth, and the world of death became one of the principal ways in which learned priests described the vertical order of creation.
These regions should not be imagined as twenty-two ordinary countries stacked directly above and below one another. A person climbing the highest mountain does not simply enter the next heaven, nor can miners reach Mictlan by digging deeply enough. The divisions describe sacred regions of existence whose relationships are expressed through height, depth, direction, celestial movement, and ritual passage.
Physical places can nevertheless approach or participate in those relationships. A mountain rises toward the celestial world. A cave descends into the body of the earth. The smoke of an offering travels upward, while blood poured upon the ground travels downward. The Sun enters the west each evening and returns from the east the following morning. The dead leave the ordinary roads of human beings and begin journeys governed by different laws.
The vertical cosmos is therefore both distant and continually present in the visible world.
The lowest celestial regions are closely connected with things visible from Tlalticpac.
The first heaven is associated with the Moon and the clouds. It lies closest to the earthly world and belongs to the changing weather and the nightly movement of the Moon.
The second heaven is the region of the stars. Nahua traditions divide the innumerable stars into great celestial companies, including the Centzon Mimixcoa, the countless northern stars, and the Centzon Huitznahua, the countless stars of the south. The number four hundred is frequently used in Nahuatl expression to signify an immense or innumerable multitude rather than a carefully counted total.
The third heaven belongs to Tonatiuh, the Sun. Across this region the Sun makes its visible daily passage from the eastern side of the world toward the west. This journey is not regarded as the movement of an impersonal object. Tonatiuh is a divine power whose continued motion belongs to the maintenance of the present cosmic age.
The fourth heaven is associated with Venus, one of the most important celestial bodies in Mesoamerican observation. Venus could appear as both morning and evening star and possessed powerful connections with Quetzalcoatl and, particularly in its morning manifestation, Tlahuizcalpantecuhtli, Lord of the Dawn. Its appearances and disappearances carried calendrical and ritual importance and could be interpreted as periods of danger.
The fifth heaven is associated in surviving descriptions with comets or smoking stars, unusual celestial phenomena distinguished from the regular movements of the fixed stars and planets.
Descriptions of the higher heavens become increasingly abstract. The sixth and seventh are associated with colors, particularly green or blue and black, and have been interpreted as celestial regions of day and night. The eighth is connected in some accounts with storms or celestial turbulence.
Above these lie heavens described through white, yellow, and red, inhabited by increasingly remote divine powers. Unlike the lower regions, which can be related to celestial bodies visible from earth, these higher places belong principally to the gods.
At the summit lies Omeyocan, the Place of Duality, associated with the highest two celestial levels in some descriptions and ultimately with the thirteenth heaven itself. There reside Ometecuhtli and Omecihuatl, the primordial lord and lady described in the oldest accounts of creation.
The ascent from the lower to the higher heavens therefore moves gradually away from the familiar sky observed by mortals and toward the most remote principles of divine existence.
The underworld is most closely associated with Mictlan, the destination of many of those who die ordinary deaths. It is ruled by Mictlantecuhtli, Lord of Mictlan, and Mictecacihuatl, Lady of Mictlan.
Mictlan is not a place of punishment for the wicked. The dead are not sent there because they failed a moral judgment, nor are those who enter it necessarily condemned. In Nahua belief, the destination of the dead depends largely upon the circumstances of death and the divine powers with which that death establishes a relationship. Those whose deaths lead toward Mictlan do so because Mictlan is their proper destination, not because it is an equivalent of a realm of damnation.
The journey is difficult.
Accounts preserved by Sahagún and in later cosmological manuscripts describe nine dangerous regions or obstacles through which the dead must pass before reaching their final rest. The exact organization and names vary, but the sequence includes passage across water, movement between or among mountains, encounters with obsidian, severe winds, places where arrows threaten the traveler, and regions in which the dead are stripped progressively of what belonged to earthly existence.
One well-known enumeration begins with a place where water must be crossed. Dogs have an important role in traditions concerning this passage, particularly the xoloitzcuintli, whose relationship with death and the underworld predates the Mexica themselves.
Other stages include a place where mountains meet or clash, an obsidian mountain, and a region of obsidian winds capable of cutting the traveler. Further places are described as those where banners are raised, where people are struck by arrows, and where hearts are devoured. The later stages approach the deepest region of the dead, culminating in Mictlan, sometimes described as the place without an opening for smoke.
These descriptions need not be understood as a single road constructed like an earthly causeway. They express the gradual separation of the dead from the conditions of mortal existence.
The complete journey is traditionally said to require four years.
Funerary rites consequently concern more than disposal of a body. The dead must be prepared for a passage that continues after their departure from Tlalticpac. Goods, offerings, and ritual acts performed by the living acknowledge the difficulties of that journey and the continuing relationship between a deceased person and the community left behind.
The ninefold underworld should not be mistaken for a universal afterlife through which every person passes.
Mictlan receives many dead, but not all deaths lead there.
Those taken through circumstances associated with Tlaloc, particularly certain deaths involving water, lightning, and particular illnesses, may be received into Tlalocan, the fertile domain belonging to the rain god. Warriors who die in battle and sacrificial victims possess a different relationship with the Sun. Women who die in childbirth likewise enter a distinctive sacred destiny connected with the solar cycle.
The afterlife is therefore organized less by a person's moral character than by the manner in which death places that person within the cosmic order.
A respected ruler and a poor farmer may both travel toward Mictlan if they die deaths belonging to Mictlan. A person of questionable conduct may nevertheless be claimed by another divine realm because of the manner of death. Earthly status does not automatically determine the destination of the soul.
This difference is fundamental to the religious understanding of death in the Fifth Sun. The gods do not maintain separate eternal kingdoms for categories of virtuous and sinful people. Death itself creates a new relationship between the individual and particular divine powers.
The full nature of these destinations, and the beings who inhabit them, belongs to the lore of death and the afterlife. What matters to the structure of the cosmos is that the dead do not all move in the same direction.
The thirteen heavens, Tlalticpac, and the nine regions below provide a model through which the vertical universe can be understood. The model is useful, but even learned traditions do not reduce the cosmos to a simple diagram.
Tlalocan, for example, belongs to the divine geography of Tlaloc but is not always placed neatly within the numbered heavens. Sacred mountains may contain supernatural spaces that do not correspond cleanly to one celestial tier. Caves can be associated with both origins and death. The Sun travels through the visible heavens during the day but enters another portion of its cosmic journey after disappearing in the west.
The universe is ordered, but its regions overlap through divine relationships.
For this reason priests distinguish between ordinary distance and sacred passage. Two places separated by many days of travel may belong to the same divine region, while a cave only a short distance from a village may approach a world normally inaccessible to the living.
The numbered heavens and underworlds are therefore best understood as a sacred ordering of existence rather than a complete map of every supernatural place.
Tlalticpac remains at their center: the inhabited surface where celestial powers descend, beings from beneath the earth emerge, the living bury their dead, and the movements of the heavens can be observed.