The Galactic Alliance is an international organisation and military alliance composed of the legitimate nations of the Milky Way galaxy, and is a development out of the Interstellar Treaty Organization. The Alliance has its headquarters in Rome, Earth. Its mission statement is "the preservation of Galactic peace and security, for all nations." Its unofficial leader, and by far the most powerful and largest member state, is the Central Galactic Union. The majority of its members are city-states on Earth, autonomous religious centres on Earth, and alien protectorates who enjoyed a previous client relationship with human states before the founding of the Republic.