From Halopedia, the Halo wiki
- Nadja Mielke, the leader of the Frieden movement, is assassinated on her way to a command center in the Europan city of Pelagon.
- The United Nations Space Command is established by the United Nations to eliminate the various rebel organizations in the Sol system.
- The Argyre Planitia Campaign takes place: In a conflict that stemmed from the Rain Forest Wars, the three primary Earth factions; the UN, Frieden and Koslovics clash again, this time on Mars. A series of lightning strikes against Koslovic forces near the Argyre Planitia marks the first extraterrestrial deployment of UNSC Marines. The campaign is deemed an unqualified success. As a result, future military doctrines favor large contingents of Marines for ground assaults and ship-boarding actions.