The United Galactic Alliance was the official federation formed and first involved only Humanity and the Sangheili. Soon all races from the old Covenant joined the Alliance, with the Humans and Sangheili serving as the main military force and the most powerful political governments within the UGA. Other races were given particular roles to control as well. It was formed after the First Apocolyptic War, when the UNSC was finally dissolved and replaced with the UGADF, or United Galactic Alliance Defense Force.