The Siege of Svivren transpired in the year 9 ABY. This conflict saw Imperial troops, dispatched under the orders of Grand Admiral Thrawn, clash with the native population of the world Svivren. The Imperial forces were ultimately unable to secure a victory in this engagement.
During 9 ABY, Grand Admiral Thrawn launched an assault on Svivren, along with several other planets allied with the New Republic. The Svivreni people, the planet's inhabitants, resisted the Imperial Navy's advances due to their strong aversion to being under siege. This unexpected resistance initially surprised the Imperials. Following a series of unsuccessful assaults against the Svivreni resistance fighters, the Imperial Navy withdrew, only to later return with the intention of occupying Svivren. The Imperials faced ongoing setbacks in their attempts to subdue the local resistance, and their predicament became widely known, even reaching Samuel Tomas Gillespee, who was residing on Ukio at the time.
Following Thrawn's demise in the Battle of Bilbringi, the Imperial forces eventually abandoned Svivren. As a result of their struggle, the Svivreni people recognized the strength of their resolve and became even more steadfast in their determination to repel any future invaders.