Coruscant

Coruscant is a leading planet within the galaxy of Galactic Prime, being the current homeworld of humans plus being the official capital of the Imperial Republic. The Emperor of the Republic resides here in the Imperial Palace, and the Imperial/Republic Senate and the Council of Moffs also meet on Coruscant.

Prior to 20,000 BR, humans, according to legends, ended up on Coruscant after traveling through intergalactic space from the planet Earth in another galaxy millions of light years away.

Coruscant originally had dozens of city-states, but they united into two nations, one controlling the northern continent of Alderaan, and the other dominating the southern continent of Corillia by year 600 BR. Alderaan was ruled by a hereditary Emperor and a similarly hereditary Council of Moffs while Corillia was ruled by a democratically elected Senate and a First Citizen elected for life by the senators.

Both nations normally were peaceful but occasionally engaged in open warfare with each other. In 51 BR, when humans had Steam Age-level technology, the alien race of Duros visited Coruscant and helped to radically advance Coruscant's technological base.

In 12 BR, Jedi missionaries came to the planet in order to teach humans their belief in the Living Force.

Humans by 1 BR decided to unite their two countries under a united government, which occured the following year (1 IR).