Ancient South American religion consists primarily of the Incan religious tradition and its precursors from the Andean region (western South America) prior to the arrival of the Spanish explorers in the 16th century C.E. These ancient traditions can be traced as far back as 2500 B.C.E. and include not only religious traditions, but the beliefs and practices that helped define the civilizations. Like other ancient religious traditions, much of the pre-Incan and Incan rituals and beliefs centered upon the holistic understanding of the people including agriculture, ritual, and devotion to the gods. A polytheistic tradition, Incan religion included many gods represented by animal idols such as jaguars and snakes. A central practice of this religion was the worship of the sun (the god was called Inti), which had its own priests to preside over the worship. In Incan religion, the creator god (Viracocha) was also important. Temples and shrines played a significant role in ancient Incan religion, often housing not only the cult relics but also the priests, their assistants, and the "chosen women." Even though the religious relics were stored inside the temples, the actual religious rituals and ceremonies often occurred outside. Two important practices within ancient Incan religion were divination and sacrifice. Divination was used to predict the outcome of battles, diagnose and heal sickness, and determine which sacrifice should be made to which god at what time. Sacrifice was essential to Incan worship and included llamas, guinea pigs, certain foods, cocoa, and even humans.