The Great Schism, also known as the Covenant Civil War, the War of Vengeance, or the Breaking of the Covenant Empire, began on October 21st, 2552, and lasted until May 14th, 2559. Initially, the Schism was a vast, internal civil war within the Covenant Empire, fought out between the Covenant Separatist and Covenant Loyalist factions, but it quickly spiraled outward and splintered the Covenant into dozens of factions, both major and minor. While the UNSC would ally themselves with the Separatists at the Battle of Installation 05 and the Siege of Earth, they would remain primarily outside of the conflict in the role of supplier and adviser after they concluded the Reclamation Campaigns, not entering heavy combat until 2557.