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. Ma'Bor Jetrel, the originator of the metreon cascade, said that he believed he had done what needed to be done. Neelix stated that he thought the war was "unjust."
One notable engagement was the Battle of the Pyrithian Gorge.
Near the end of the war, Talaxian Defense Forces on Talax prepared for a Haakonian invasion. The war ended when the Haakonians deployed a devastating weapon known as the metreon cascade on the Talaxian moon Rinax. More than a quarter of a million Talaxians were vaporized, 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 death.
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 sympathizer and be exiled from his homeworld. (VOY: "Jetrel")
Following the war, the Haakonians continued to control Talax well into the 2370s. A number of Talaxians left Talax because of how the Haakonians treated them. In 2378, Voyager encountered a group of five hundred 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")