Robert Parker in On Greek Religion, discusses the different key themes that occur within Greek religion. Parker focuses on what he believes to be key themes in ancient Greek religion. These themes include theories of sacrifice, the nature of heroes and gods, the basis of Greek religion, the meaning behind feasts, rituals, and festivals, and aspects of religious authority. He uses information from the Archaic Period, the Classical Period, and the Hellenistic Period in order to support his main points. He also includes the varieties of Greek religion within the information he provides to his readers. Parker, throughout his book, discusses evidences of Greek religion, religious authority in Greece, analysis of Greek gods, the nature of heroes,
