Aztec mythology has been in mexico since before mexico was called mexico, it has been around since the Aztecs one of the first inhabitats of Mexico which is around the 1300's. the Aztecs beliefe was that the gods and goddess and spirits ruled the world, and to keep them from dying they must give a blood sacrifice. One of these many beliefs was that the the god of the sun HUITZILOPOCHTLI was in a battle with the darkness and that the blood sacrifice keept him from dying. this sacrifice was done every 52 years. which has to do with their calendar and the corresponding gods to everyday, and the 4 types. every year gets detected to a different god, but every day gets detected to a different god or spirit or element. the 4 differnt types of calaenders are hard to understand but befer the years starts it is given a type - Calli, Tochtli, Acatl and Tecpatl - so in total every 52 years (4 x 13) the ritual is conducted. the biggest reason for the aztecs beliefe was there land they were very into agriculture and without the sun nothing would have been grown. so prying sacrificing and all the beliefe was due to necessity, they needed food, and a livable place.