Established and supervised by the Jedi-Bendu, a cadre of bodyguards that had faithfully defended the many Emperors for at least 100,000 years, the Imperial Space Force had expanded the Galactic Empire from the celestial equator to the Great Rift. However, the Great Jedi Rebellion would see the Jedi-Bendu come into conflict with the Emperor, leading to their expulsion and manhunt which in turn enabled the ascension of Cos Dashit to the position of sovereign and the Knights of the Sith assuming the mantle of his protectors.
Decrying the Aquilaean system's stance as the sole remaining state independent of the Galactic Empire and deeming the attempted negotiations with the Aquilaeans a waste, the Emperor announced the beginning of his upcoming campaign against them, which Governor Crispin Hoedaack and General Darth Vader - the true powers behind the scenes - would spearhead with the Imperial Star Force and the Space Fortress battle station at their disposal. The ambush and killing of King Kayos during General Luke Skywalker's daring attack daunted the Aquilaean Senators and Queen Breha into pushing for a peaceful resolution and having the old Jedi-Bendu down. Following the self-destruction of the Hidden Fortress, General Vader summoned Prince Valorum, a Knight of the Sith, to find and eliminate General Skywalker and his ragtag rebel troop, with Stormtroopers and hover tanks also on the lookout for the fugitives. Ultimately, Annikin Starkiller and Princess Leia were captured by Imperial forces and hauled to the Space Fortress, awaiting execution at the behest of General Vader, only to escape with the aid of the disillusioned Prince Valorum. Shortly afterwards, General Skywalker and his assembled Wookiee squadron assaulted and crippled the battle station, dealing a heavy blow to the Imperial Space Force and scoring the rebels' first major victory against the Galactic Empire.
Stardestroyers of the Imperial Space Force
The Imperial Space Force is called the Imperial Navy or Imperial Fleet in the finished films and Expanded Universe. Deriving from the original concepts, the creation of the galaxy's principal military force, the Grand Army of the Republic, by the Jedi followed by its usurpation by the Sith and subsequent transformation into the oppressive Imperial Forces occurs in Episode II and Episode III.