The rise of Switzerland as a federal state began on 12 September 1848, with the creation of a federal constitution, which was created in response to a 27-day civil war in Switzerland, the Sonderbundskrieg. The constitution, which was heavily influenced by the United States Constitution and the ideas of the French Revolution, was modified several times during the following decades and wholly replaced in 1999. The constitution represents the first time that the Swiss were governed by a strong central government instead of being simply a collection of independent cantons bound by treaties.