The Battle of Earth was one of the largest engagements fought between the Covenant and the United Nations Space Command, which took place on and above the planet Earth and across the Sol system from October 20, 2552 to November 17. It was one of the most significant battles of the Human-Covenant war as the fate of humanity depended on the survival of their homeworld. The battle concluded when the Prophet of Truth's Dreadnought left Earth through the Portal with the purpose of activating the Halo Array from "The Ark".