Selene has a long and important history in the galaxy. An important Core world, Selene is located at the end of what is now known as the Tarkin Corridor, which proved invaluable to the Galactic Empire following its fragmentation in 4 ABY.
Selene was a member world of the Old Republic and was home to a largely Human population. During the Clone Wars, Selene became the site of a large Republic fleet presence and soon a location for both Kuat Drive Yards and Sienar Fleet Systems resources.
Selene was spared from the direct effects of the War, and soon became one of the foundation worlds in the newly formed Galactic Empire. Its sector moff, Ardus Kainel, was a staunch supporter of the New Order and the Tarkin Doctrine, and kept strict control over Selene.
The shipyards at Selene produced warships and starfighters for the Imperial war machine, and as such, was considered a strategic target by the Rebels at the start of the Galactic Civil War. But, due to its location in the Core, and proximity to worlds such as O'paal and Coruscant itself, the Rebels never made a successful effort to hit Selene.
After the Battle of Endor, Selene became a staging point for loyalists to the Imperial Ruling Council, and the fleet positioned at Selene would soon supplement the Imperial Center Defense Force during the Battle of Coruscant.
After the fall of Imperial Center to the Rebels, and the formation of the New Republic, loyalists fell back on Selene to guard the vital shipyards. Warlords whom broke off from the Empire during the Post-Endor Imperial power struggle made several attempts to claim Selene over the four years of warring, but the Interim Ruling Council refused to let go of Selene, despite its capital being located distantly in the Outer Rim at Dreven.
In 7 ABY, Selene became host to the construction and launching of a new Executor-class Star Dreadnought, the HIMS Palpatine, which Bacharan Valak, current ruler of the Empire and soon-to-be Galactic Emperor, took as his flagship. Selene then became the staging point for Valak's great campaign at the start of 8 ABY, reclaiming a vast amount of territory in a relatively short amount of time, including Coruscant itself.
Selene rose in prominence afterwards, and a new swoop track, the Sunbird Eyrie Stadium, was built on Selene to attract more tourists. After the abdication of Emperor Valak, Kendal Osbourne became Emperor and chose Selene as the new Imperial capital. Things, however, would take a turn for the worst in a relatively short time.
Lorn Rhys had returned, defying the belief of his supposed execution following the eradication of the Vigilant Movement in 7 ABY, and launched a coup against Osbourne. Hijacking the Dark Eminence, Lorn and his Whitecoats plunged the dreadnought into the planet as the closing stroke of the Battle of Selene, causing an environmental catastrophy. Life of all kinds died in a matter of days, and the planet was rendered sterile. The War of the Throne had begun, and the Imperial capital defaulted to Dreven.
Selene remained a wasteland for nearly a year, until the termination of the War and the rise of Warlord Malign, who appointed Scaven Marx as Grand Moff with the task of reconstructing the once glorious Imperial world. A vast amount of automated laborers were used in the work on Selene. A gigantic domed city was built over the former Imperial City, protecting the new settlement from the radiation and toxins of the Wastelands. Certain buildings in the new Imperial City even went so far as to connect with skyhooks in orbit around Selene, and then on to the Kuat Drive Yards-Sienar Fleet Systems space station. Imperial City was rebuilt, albeit not quite to its former splendor. Selene served as the capital to Malign's military government, but the Imperial capital was moved back to Coruscant following its retaking by Imperial Forces during the Imperial Blitzkrieg.