Following the creation of the galaxy around the year 13,000,000,000 BBY, stars began to form within it, developing planets and becoming star systems. One of these systems, which would go on to be called the Goroth system, developed around a star named Goroth Alpha, with a second, Goroth Beta, orbiting. After several millennia in existence, the system had four planets revolving around Alpha between the suns. The system's second planet would become known as Goroth Prime.
5,000,000,000 BBY, or 5,000,000,000 Before the Battle of Yavin, was a year of the Galactic Standard Calendar that fell within the Pre-Republic era. Xenobiologists native to Goroth Prime who lived during the reign of the Galactic Empire, formed in 19 BBY to begin the Imperial Period, studied their planet's biological history. Their estimates placed the world's first forms of life as emerging by the year 5,000,000,000 BBY.
Those forms of life evolved over billions of subsequent years until achieving semi-sentience one million years before the Battle of Yavin, the epoch of the Galactic Standard Calendar. This was relatively late when compared to the rest of the galaxy. The fully sentient Gorothites then emerged 990,000 years after that.
5,000,000,000 BBY was mentioned in West End Games's Goroth: Slave of the Empire, a 1995 expansion to Star Wars: The Roleplaying Game written by Nigel D. Findley. It was then established in The Essential Guide to Alien Species (2001) by Ann Margaret Lewis as the approximate birth year of the galaxy. The juxtaposition of these events caused something of an issue, as it took many millennia to form planets. The Essential Atlas (2009) by Jason Fry and Daniel Wallace later clarified the year 13,000,000,000 BBY as the approximate birth of the galaxy, rectifying this potential inconsistency.
The Expanded Universe practice of dating its events using the Battle of Yavin as an epoch was standardized out of universe with the release of The Essential Chronology in 2000. It did not formally exist when Goroth: Slave of the Empire came out in 1995. The specific reference within Goroth was relative to the events of that expansion, which occur at a time vaguely during the Galactic Civil War, the conflict during which the Battle of Yavin took place.
- Goroth: Slave of the Empire
- The Essential Guide to Alien Species
- The Essential Atlas