The Oriana Campaign was a major tactical and strategic offensive major offensive by the United Nations Space Command, Alliance of Sangheili Clans and Yanme'e Conglomeration, taking place between late May and early July 2565. The strategic offensive element, comprising the Oriana system and three surrounding systems, saw over twelve million troops devoted to it, while the tactical offensive, taking place on and around Oriana itself, intended to defeat the Covenant military presence on the world. This presence would otherwise have all but halted any UCG advance on Glorious Salvation, the Covenant Remnant's homeworld. The campaign began on 26 May with the UNSC Navy's advance into Covenant territory, and concluded in the first week of July with the defeat of the fortress world of Oriana. This