One of the key functions of mythology in many societies is to provide an explanation or origin story for social norms and customs. This lecture will focus on one such myth from the ancient Greek world. The story of the trickster Prometheus' deception of the gods formed the basis for how and why the Greeks honoured their gods through the dedication of sacrificial animals, the central practice in Greek religion. In this lecture, we will explore how sacrifice was practiced in ancient Greece and why the Greeks might have needed a myth to justify how they approached it.