THE CHKONOLOGICAL CALENDAE 



23 



THE AHAU. 



This period is the real hasis of the Maya chronological system. Everything proceeds 

 by ahaus, till in succession the katuns, cycles, great cycles, and grand era are formed 

 from them. 



The ahau is a period of 360 days — the sum of the days in the eighteen regular 

 months — and derives its name undoubtedly from the fact that it always begins with 

 the day Ahau. It is the period, not between two Ahaus with the same numeral, but 

 between the second two with a differentiation of four in their day numbering. Moving 

 forward with this progression of four it results that the ahaus follow each other in the 

 order of 9, 5, 1, 10, 6, 2, 11, 7, 3, 12, 8, 4, 13, 9, 5, 1, and so on— an order of 

 succession that Perez quotes from an unnamed manuscript, but whose significance 

 he failed to grasp. 



Twenty ahaus constitute a katun. They are numerated : 20, 1, 2, 3, etc., up to 19. 



