A treaty is a formal agreement between two or more nations, relating to peace, alliance, trade, etc. A few examples include the Treaty of Ghent (1814) which concluded the War of 1812; the Adams-Onís Treaty (1819) which settled a boundary dispute related to the Louisiana Territory; Treaty of Guadalupé Hidalgo (1848) which ended the Mexican American War; Treaty of Paris (1898) which ended the Spanish-American War; and the Treaty of Versailles (1919) which officially ended World War I;