The United Empire developed from a fleet of Mezari settlers on a temperate, resource-rich world. For decades commercial and industrial effort went into the conquest and development of the planet. Once the planet was largely colonized and controlled, a more or less inevitable event occurred: The Great Continental War. This planet-wide military conflict occurred at a technological level that might have led to total extermination of life, and the rulers were wise enough to pull back from the brink of this collective suicide. The dominant force at the end of the war, known as the Alliance of Nations, imposed its will across the entirety of the planet through a mixture of rebuilding loans, military threats, and moral persuasion.
Advanced space technologies have thus been developed under a single body that put a great deal of effort into it, and space exploration occurred at a rapid rate. The Mezari–now calling themselves Raians–launched manned probes to distant bodies within their solar system, and as technology advanced, the next steps back to the stars were inevitable.