The United Nations of Earth (UNE) was the first Human unified government, founded in SEY 2380, shortly after the first planet outside the Sol system was successfully terraformed.
The world leaders of the time decided that Humanity's expansion into space would be better managed by a unified government. Existing countries formed the first Senate and supervised the first major terraforming boom in Human history and the first diasporas from Earth. It was peacefully reformed as the United Planets of Earth in 2523.