1 Coatl

Trecena 9 opens on 1 Coatl, the serpent, under the joint patronage of Xiuhtecuhtli, the turquoise fire lord, with Tlahuizcalpantecuhtli, lord of the dawn house, an aspect of Quetzalcoatl as the morning star, standing beside him in the codices, a pairing of fire and Venus that gave this trecena an unusually bright astral character among the twenty. Sahagun reads the serpent week as a travelling week: 1 Coatl was a day the pochteca, the long distance merchants whose expeditions carried goods and intelligence across Mesoamerica, favoured for setting out, and the trecena as a whole reads as fortunate for enterprise and exchange, a week of roads opening and goods in motion.

The serpent sign itself carries associations with renewal across Mesoamerican thought generally, tied to the shedding of skin, and its pairing here with a fire and dawn star patronage reinforced a reading of movement and fresh beginning that merchants setting out on long, dangerous journeys would have wanted behind them. Xiuhtecuhtli's appearance as a trecena patron here is a separate role from his standing as the first of the nine Lords of the Night, the two systems of trecena patrons and night lords assigning him duties that run alongside each other rather than merging into one.

Trecena 9 runs from 1 Coatl through 13 Ollin, movement, its span carrying serpent, death, deer, rabbit, water, dog, monkey, grass, reed, jaguar and eagle before closing on the sign that names the present cosmic age, Nahui Ollin, four movement, and opens Trecena 13 next in the round. Sitting almost exactly at the tonalpohualli's midpoint, this trecena's closing day sign carries weight far beyond its role here as the final day of a merchant's favourable week, since Ollin names the whole era the Mexica understood themselves to be living within, the fifth and, in their belief, final sun, fated eventually to end in earthquake.

A diviner reading this trecena's later numbered days, as the count approached thirteen and the movement sign, would have felt the pull of that larger cosmological association even while giving a routine reading for a birth or a departing trade caravan. The pochteca's own calendar of departures, described in general terms by Sahagun and Duran, treated favourable trecenas like this one as genuinely practical information rather than abstract belief, since a merchant's livelihood and survival on the road depended on choices the tonalpouhque's readings were consulted to inform.