Homeworld of humanity, main world of the CoDominium. Also provided mercenaries in the late CD era, but they were not the best. During the Great Patriotic Wars, Earth receives heavy damage - although the Alps and Jamaica survive - and ceases being the center of Human civilization.
However, Earth is still inhabited by the Second Empire, if badly damaged, and used as an honorary capital. The Naval Academy is located on Earth, at New Annapolis, partly to remind cadets of why the Empire is vital to humanity's survival.