The Sonderbund War of November 1847 was a civil war in Switzerland, then still a relatively loose confederacy of cantons. It ensued after seven Catholic cantons formed the Sonderbund in 1845 to protect their interests against a centralization of power. The war concluded with the defeat of the Sonderbund. It resulted in the emergence of Switzerland as a federal state, concluding the period of political "restoration and regeneration" in Switzerland.