Greek religion was a complex and integral part of ancient Greek society, having a great influence on its culture, politics and daily life. It was polytheistic, centered on the worship of a pantheon of gods and goddesses, each associated with certain elements of life and the natural world. It was believed that gods and goddesses could change the course of events in a person's life, therefore, in order to gain the favor of the gods, various rituals were held in their honor. They included prayers, sacrifices, gifts, dances, games. Along with public religion, there were also secret religious traditions such as the Eleusinian Mysteries, which appeared around the third millennium BC. They were based on the myth of Demeter and Persephone, and their members were promised profound eschatological promises. Mysteries attracted many throughout different periods and social strata in Greek and Roman society. Those who wanted to become members had to go through an intensive initiation that was divided into two parts, mýēsis and epopteía. If they went through the entire initiation process, new members were promised a more favorable afterlife, which contradicted the traditional Greek belief that the afterlife was a dark existence in the underworld.