The Talaxian-Haakonian War was a war fought between the Talaxians and Haakonian Order "for a better part of a decade" from the mid-2340s to the mid-2350s. The war concluded in 2356, when Talax surrendered and became occupied by the Haakonian Order.
The details of the war, outside of the conquest, were unspecified; however, Neelix stated that he thought the war was "unjust."
One of the final battles of the war was the Battle of the Pyrithian Gorge, where Talaxian Defense Forces prepared for a Haakonian invasion. While the battle was fought, the invasion never came, as the Haakonians deployed a devastating weapon known as the metreon cascade on the Talaxian moon Rinax instead. More than a quarter of a million Talaxians were vaporised, and the following day Talax surrendered unconditionally to the Order.
Neelix, who lost his entire family due to the metreon cascade, was hiding on Talax from the Talaxian Defense Forces at the time the cascade was deployed; he was guilty of desertion and illegally refused to serve. While this fact was never discovered by the Talaxian authorities, had he been caught during war time, his punishment for "refusing military service" would have been the death penalty.
Ma'Bor Jetrel, the Haakonian scientist who had lead the development of the metreon cascade, spent the rest of his life attempting to undo some of the damage his weapon had caused. This lead him to be labeled a Talaxian sympathiser and be exiled from his homeworld. (VOY: "Jetrel")
In 2378, Voyager encountered a group of refugees of 500 such refugees, that were living on an asteroid colony near the Beta Quadrant. Dexa's son, Brax, upon learning more about his homeworld, thought that "maybe Neelix could go with [them] and [they] could fight them, [and] take the planet back," after Neelix had demonstrated to the colonists his intentions to protect them from persecuting miners. (VOY: "Homestead")