facts · 18 × 20 + 5

Veintenas are not European months

This table follows the Sahagún-family sequence analysed by Bartl, Göbel and Prem. Every regular period lasts twenty days; five nemontemi complete the nominal annual structure.

Eighteen twenty-day periods in the selected witness family
position	name	recorded alternatives	nominal days
1	Cuahuitlehua	Atlcahualo	1–20
2	Tlacaxipehualiztli	—	21–40
3	Tozoztontli	—	41–60
4	Hueytozoztli	—	61–80
5	Toxcatl	—	81–100
6	Etzalcualiztli	—	101–120
7	Tecuilhuitontli	—	121–140
8	Hueytecuilhuitl	—	141–160
9	Tlaxochimaco	Miccailhuitontli	161–180
10	Xocotlhuetzi	Hueymiccailhuitl	181–200
11	Ochpaniztli	—	201–220
12	Pachtli	Pachtontli · Teotleco	221–240
13	Hueypachtli	Tepeilhuitl	241–260
14	Quecholli	—	261–280
15	Panquetzaliztli	—	281–300
16	Atemoztli	—	301–320
17	Tititl	—	321–340
18	Izcalli	—	341–360
extra	Nemontemi	five completing days	361–365

Why 52 appears

73 ritual counts18,980 days

52 nominal years18,980 days

least common multiple18,980 days

INAH connects this cycle with the Mexica New Fire ceremony and the binding of years. The equation describes the nominal counts; it does not settle how seasonal adjustments operated over long spans.

Even the familiar labels need a footnote

Bodhastra keeps xiuhpohualli and xiuhmolpilli because readers and much scholarship use them. Gabriel K. Kruell’s source-based terminology instead distinguishes tonalpohualli, cempohuallapohualli and xiuhtlapohualli. The site records that disagreement instead of silently declaring one vocabulary timeless.

Read the terminology and New Fire sources →