The Sonderbund War was a civil conflict in Switzerland that took place in 1847. It was fought between the Sonderbund, a coalition of seven Catholic cantons, and the rest of the country, which was predominantly Protestant. The war arose from tensions over political power and religious differences, as the Catholic cantons sought to maintain their autonomy against the growing influence of the federal government. The conflict lasted for just 26 days, from November 3 to December 29, 1847. The Swiss Federal Army defeated the Sonderbund forces, leading to the dissolution of the coalition. This war ultimately contributed to the establishment of a more unified and centralized Swiss Confederation in 1848.