Fortress world A Fortress world was a massively - protected planet . Most fortress - worlds were designed to serve as military and political strongholds of various factions . They played a particularly important element in Imperial strategy after the Battle of Endor , designed to resist New Republic assault and — at least in theory — provide the basis for a subsequent Imperial reconquest . Origins . The term " fortress world " dated back at least as far as the early days of the Galactic Republic , when it described worlds like Anaxes , which held massive concentrations of warships and defensive emplacements . The term gained prominence during the Clone Wars , when the Confederacy of Independent Systems concentrated armies of battle droids , self - replicating war factories and large fleets around planets in the Outland Regions , in order to draw the Republic into the costly and protracted Outer Rim Sieges . Sullust , Siskeen , Boz Pity and Xagobah were examples of Separatist fortress worlds . The Republic also had fortress worlds , located in the Core Worlds region . Protection of Republic fortress worlds was among the duties of the V - wing starfighter squadrons during the war . Imperial developments . The fortress worlds of the Galactic Empire , however , were created not to force battle on the defenders ' terms , but to discourage attack altogether . The first Imperial fortress worlds were established in the heyday of the New Order as models of Palpatine ' s political vision , exemplified by planets such as Prakith and Byss which were colonized in the Deep Core . They were peopled with loyalist Human settlers and nonhuman slaves , all living in order and security under the watchful gaze of the Inquisitorius and behind massive orbital defenses almost comparable to those of Coruscant itself , capable of protecting these worlds from any potential threat . Coruscant , of course , acquired many of the trappings of a fortress world in its own right , including a massive grid of orbital battle stations and an entire sector fleet with a Super Star Destroyer command ship deployed to the system . The renaming of the planet as " Imperial Center " was designed to stress its new status as the center of the New Order , but the teeming reality of Coruscant could only be constrained by force or the threat of force , never fully ordered and controlled in the way that was attempted on the fortress worlds . From Endor to the collapse of the Ruling Council . After the deaths of Palpatine and Darth Vader , the term " fortress world " gained new importance as the Empire was forced into a defensive strategy by the Rebel Alliance . Led by Ars Dangor , surviving members of the Imperial Ruling Council recalled fleet elements to the Core and concentrated them around key planets . Kuat , for instance , was guarded by fifteen Imperial Star Destroyers , while Tangrene was always covered by at least two " Imperial " - class ships and ten smaller warships . The planets chosen for protection were worlds with significant roles in Galactic geopolitics , often major hyperspace junctions or key elements of the Empire ' s military - industrial and commercial infrastructure . Although members of the Ruling Council had long been working to subject these same worlds to their own private authority , their retrenchment was strategically sound . Fortress worlds served as bastions of the New Order : beacons of stability and control or centers of tyrannical power , depending on one ' s point of view . The concentrations of Imperial forces around these heavily - defended strongholds could not be dislodged in the short term , while their repositioning simultaneously compelled the nascent New Republic to fill the gap in territory they had abandoned . Many in the Empire continued to believe that the Rebels could not form a viable government ; their political system would inevitably collapse , and the galaxy would greet an Imperial reconquest with the same relief that they had shown in the aftermath of the Clone Wars . However , it would be wrong to suggest that the fortress worlds served simply as the expression of an organized strategy with the ultimate goal of galactic reconquest . Even the most blindly committed of the Empire ' s leaders must have questioned whether they would truly win the war , and fortress worlds served as strongholds raised against an anarchic galaxy , where a governor , commander or opportunist could sustain an ideal of order and discipline , or a vicious personal autocracy . As a result , it seems that many individual warlords and Moffs began to imitate the Ruling Council on a local scale , bringing together forces and resources from the sectors they controlled , acting on their own initiative to turn selected planets into personal redoubts . A temporary pause was marked by the return of Grand Admiral Thrawn : as the Empire once again went on the offensive , the Grand Admiral ordered Star Destroyers to redeploy from planetary - defense duties to join his front - line fleets , replacing them with Dreadnaught Cruisers with Imperial Army crews . This was , in fact , nothing more than the second stage of the Empire ' s reconquest strategy , to which the creation of the fortress worlds had always been intended as a prelude . But while the Ruling Council and the Navy continued with their strategy after Thrawn ' s death at the Battle of Bilbringi , many Moffs and warlords turned once again to building up their planetary bastions , and the process of fortification gathered pace once again during the period leading up to the Imperial Mutiny . Examples of this second wave of fortress worlds included Gyndine , guarded by thirty capital ships , and Aargau with at least two hundred . Many of these new fortress worlds had planetary shields , and where possible , these were surrounded by outer layers of defenses , including antimatter minefields and airless moons converted into military bastions with batteries of heavy turbolasers and ion cannons . Endgame and aftermath . After the final death of Palpatine ' s last clone and the collapse of the rump Ruling Council on Ord Cantrell , the fortress worlds drew in upon themselves . The New Republic claimed that the Empire had been destroyed , but the reality was that , although no central authority existed , the defenses of planets like Prakith and Carida discouraged immediate assault , and the Navy lacked the resources to round up the garrisons on backwater planets . Thus , the fortress worlds remained intact as the primary expression of the New Order , their population further swollen by loyalist refugees from across known space . The remnants of the Empire gradually coalesced under the authority of the Council of Moffs , who handed over strategic command to Gilad Pellaeon , the former flag captain of Grand Admiral Thrawn . Pellaeon ' s instincts as a commander were to face the Rebels with maneuver warfare and fleet battles , and while political considerations saw heavy defenses built up around besieged outposts such as Orinda , conventional fortress worlds became rare in what remained of Imperial space . The planet that conformed most closely to the model was Yaga Minor , with its massive military presence and native population of alien laborers — although even here the defenses were designed to protect the system ' s shipyard facilities , not the world itself . The economic powerhouse at Muunilinst was guarded only by three Golan battlestations , while the capital at Bastion lacked such orbital defenses altogether , instead relying on the thirteen Star Destroyers of the local sector fleet for its protection . While the First Fleet and Third Fleet faced Pellaeon ' s forces on the battle plane , the New Republic created the Fifth Fleet as a strike force which could take even the most heavily - defended fortress worlds . During the New Republic ' s offensive after the Almanian Crisis , several perimeter fortress worlds fell to New Republic forces , and after the signing of the Bastion Accords , the Republic continued to liberate isolated strongholds , particularly in the Deep Core . By the time of the Yuuzhan Vong War , it seems that most of the fortress worlds had been conquered , their defenses dismantled . A number of planets along the frontier of Imperial Space , such as Borosk , were fortified as frontier redoubts , but of the major fortress worlds , only Yaga Minor now remained — and it can be noted , somewhat bleakly , that whereas the invaders overwhelmed Bastion and Muunilinst with terrifying speed , the defenses of the Empire ' s key shipyard threw off the Yuuzhan Vong with remarkable ease , no less than twice . As of 130 ABY , Bastion had become known as the best - defended fortress world in the galaxy , making a direct attack by Darth Krayt ' s Galactic Empire against the capital of Roan Fel ' s Empire - in - exile virtually impossible .