Elivagar was a mining fleet that went rogue on the edge of space during the events of Space Pilgrim Academy: Year 3.
Over the course of a few months in 2216, the fleet was the target of persistent pirate attacks. Many lives were lost. The miners felt they were not being sufficiently protected by the Galactic Union, so they elected to declare independence and go and look for an uninhabited planet to settle on.
See also: Elivagar Flagship.