Trecena 7, Opening on Quiahuitl

Trecena 7 opens on 1 Quiahuitl, rain, under the patronage of Tlaloc, giver of rain and among the oldest deities attested in central Mexico, his cult traceable in the archaeological record to Teotihuacan long before the Mexica adopted him as one of the two gods honoured at the templo mayor's twin shrines. Sahagun's fourth book calls this the sorcerers' week, recording that the nanahualtin, the shape changers of Nahua belief, were said to be born within it, and its days read as dangerous, apt for illness and for uncanny meetings that a traveller or a household head was warned to guard against.

An unfavourable week overall, its power, the readers held, could be turned by offering but never simply ignored, a formula the sources apply to several of the count's harder trecenas but state with particular force here, in keeping with Tlaloc's own double character as a god equally capable of nourishing rain and destroying storm. The rain god's patronage of a week associated with shape changing sorcery draws on the same logic that linked him to mountain caves and to the tlaloque, his company of lesser rain spirits, since caves and mountains were the places Nahua cosmology treated as thresholds where ordinary reality gave way to more dangerous forces.