Great Journey

Summary
In the Covenant's mythology, the Great Journey is a transcendence that makes one a god. The Prophets and the Elites were once at war with each other. Then the Prophets discovered a myth that the Forerunners built seven Halos around the galaxy, activated them, went on their Great Journey and became gods. The races formed an alliance, the Elites pledging to protect the Prophets as they searched for the rings.