“Xiuhtecuhtli (Turquoise Lord) * Tecpati-Itzli (Lord of the Obsidian Blade) * Piltzintecuhtli (Our Lord Prince) * Centeotl (Lord of the Maize) * Mictlantecuhtli (Underworld Lord) * Chalchiuhtlicue (Lord of the Jade Skirt) * Tlazoteotl (Our Lady of Two Faces—Lustful Sin and Purification) * Tepeyollotl (Lord of the Heart of the Mountain) * Tlaloc (Lord of Rain and Fertility)
The Aztecs, like most of the pre-Columbian civilizations of Mesoamerica, ran a number of sacred calendars concurrently, which made life more interesting, in terms of working out festivals and celebrations, as well as good, bad, propitious and impossible days, nights and months. Blocks of nine nights fitted into both the 365-day-long solar year (known as Haab), which was divided into twenty groups eighteen-day months, as well as the 260-day-long fertility calendar (known as Tzolkin) composed of twenty groups of thirteen-day months as well as twenty-nine groups of nine nights.
Twenty-nine is of course the unit of a lunar month, while nine months represent the gestation of both a human child and the complete tropical cycle of sowing to reaping for such vital crops as maize. So the Lords of the Night, in some South American cultures, appear also as the Lords of the Nine Months, or the Nine Judges of Hell, and other ninefold manifestations.”
Excerpted from: Rogerson, Barnaby. Rogerson’s Book of Numbers: The Culture of Numbers–from 1,001 Nights to the Seven Wonders of the World. New York: Picador, 2013.