1 Ollin

Trecena 13 opens on 1 Ollin, movement, under the patronage of Tlazolteotl, the earth goddess called eater of filth, patron of the once in a lifetime confession rite, neyolmelahualiztli, the straightening of the heart, through which a penitent could clear serious transgression before a priest acting in her name. Sahagun's informants read the movement week's children toward fortune or ruin with little middle ground, an augury of extremes fitting for the sign that names Nahui Ollin, four movement, the present cosmic age the Mexica believed themselves to be living within and which their own cosmology held would eventually end in earthquake, the sign's own violent, unstable meaning built directly into the era's name.

A week of turning points, favourable to the decisive by the readers' judgment, its patronage by a goddess whose whole cult centred on clearing old transgression to make a fresh start fits the movement sign's theme of dramatic change precisely: both goddess and sign concern the passage from one state to a decisively different one, whether through confession's clearing of the past or the cosmic age's eventual violent renewal. Tlazolteotl's patronage here, as trecena patron, is a distinct role from her separate standing as the seventh of the nine Lords of the Night, the two offices assigned independently in the surviving codices.

Trecena 13 runs from 1 Ollin through 13 Atl, water, its span carrying movement, flint, rain, flower, crocodile, wind, house, lizard, serpent, death and deer before closing on the sign that opens Trecena 17 next in the round. This trecena sits just past the count's midpoint, and its opening day sign, carrying the same name as the present cosmic age, gave it a symbolic weight in Mexica thought that outran its ordinary place as merely the thirteenth of twenty trecenas, since Ollin's association with the fifth sun's eventual end by earthquake meant readers and clients alike approached this week aware of a cosmological resonance most trecenas did not carry.

The extremes of fortune the readers attached to this week's children mirror the movement sign's own reputation elsewhere in Mesoamerican calendrics as one of the most consequential and unpredictable of the twenty, a reputation this trecena's status as Tlazolteotl's week, governing confession and the clearing of the past, reinforces rather than softens. The thirteen numbered days within this span, read against their patron birds and against each day sign's own character, gave the tonalpouhque considerable room to distinguish a favourable from an unfavourable birth within what the trecena as a whole announced only as an extreme, fortune or ruin, rather than a single fixed outcome.