The National Constituent Assembly was a unicameral legislature of the Kingdom of France that existed from 13 June 1789 to 30 September 1791, containing 1,315 seats. The assembly was formed by representatives of the Third Estate after they were locked out of the Estates-General and swore the "Tennis Court Oath", promising to not disband until the absolute monarchy was overthrown. The National Assembly would succeed in creating a constitutional monarchy after the Storming of the Bastille, and the National Assembly would be replaced by the Legislative Assembly after a constitution was signed in September 1791.