 Huitzilopochtli was said to be in a constant struggle with the darkness and required nourishment in the form of sacrifices to ensure the sun would survive the cycle of 52 years, which was the basis of many Mesoamerican myths.There were 18 especially holy festive days, and only one of them was dedicated to Huitzilopochtli.This celebration day, known as Toxcatl, falls within the fifteenth month of the Mexican calendar.