Congress, in international politics, an assembly of the sovereigns or plenipotentiaries of several states to determine questions and concert measures of common interest. The term is of modern origin, the earliest important European congress having been that of Minister and Osnabrilck, which assembled in 1644, and concluded the peace of Westphalia in 1648. The subsequent congresses or conferences of most general interest have been those of the Pyrenees (1659), of Nimeguen (1676-'79), of Ryswick (1697), of Utrecht (1712-'13), of Aix-la-Chapelle (1748), of Teschen (1779), of Ra-stadt (1797-'99), of Erfurt (1808), of Chatil-lon (1814), of Vienna (1814-'15), of Aix-la-Chapelle (1818), of Carlsbad (1819) and Trop-pau (1820), of Laybach (1821), of Verona (1822), and of Paris (1856). - The term congress is also sometimes given to literary and scientific associations. It is also the designation of the combined senate and house of representatives which make the legislative branch of the government of the United States and the Spanish American republics, and of the house of representatives in the Spanish cortes.