Richelieu, Armand Jean du Plessis, duc de (Cardinal Richelieu), 1585-1642, French prelate and statesman, chief minister of King Louis XIII, cardinal of the Roman Catholic Church. Consecrated bishop of Luçon (1607), he was a delegate of the clergy to the States-General (1614). In 1616, through the favor of the king's mother, Marie de' Medici, he became a secretary of state. He went into exile with Marie after the king freed himself from her influence with the aid of the duc de Luynes. The death (1621) of Luynes and the reconciliation of Louis XIII and Marie restored Richelieu to favor. In 1622 he was made cardinal, and he became chief minister in 1624. The growing jealousy of Marie and the great nobles endangered his position, and in 1630 Marie supported a conspiracy against Richelieu. She was unable to win the king's support, however, and was exiled. Richelieu then had full control of the government. His domestic policy aimed at consolidating and centralizing royal authority, which had as its corollary the destruction of the power of the Huguenots and the great nobles. The Huguenots were humbled by the capture of La Rochelle (1628); the peace of Alais (1629) ended their special political privileges—without, however, denying them religious toleration. Conspiracies of the nobles, who invariably found a figurehead in the king's brother Gaston d'Orléans, were rigorously suppressed. In foreign affairs, Richelieu reacted against Marie de' Medici's pro-Hapsburg diplomacy in favor of the traditional French anti-Spanish and anti-Austrian policy. To this end he strengthened the army and the navy, made alliances with the Netherlands and the German Protestant states, and subsidized Gustavus II of Sweden against the Holy Roman Emperor in the Thirty Years War. In 1635 he formed an active alliance with Sweden and Bernhard of Saxe-Weimar, and France entered the Thirty Years War. Although Richelieu died before the peace was signed (1648; see Westphalia, Peace of), the terms agreed to were in general conformity to his aims. In France, the war resulted in heavy taxation; this, combined with Richelieu's poor management of finances, depleted the treasury and caused dissatisfaction with his rule. Overseas, however, he encouraged commercial capitalism, organizing companies to trade in the Indies and Canada. He was a patron of the arts and the founder of the French Academy. Among his literary works are his memoirs (1650) and the Testament politique (1688, tr. 1961).

Richelieu, Armand Emmanuel du Plessis, duc de, 1766-1822, French statesman. An émigré from the French Revolution, he served Russia as governor of Odessa (1803) and of the Crimea (1805). Made chief minister of France by King Louis XVIII after the Hundred Days (1815), he secured the quick payment by France of the indemnity imposed by the second Treaty of Paris (1815) and thus hastened the evacuation of occupation troops. In his domestic policy, Richelieu favored leniency toward the ex-revolutionists and Bonapartists, thus displeasing the ultraroyalists headed by the king's brother, the comte d'Artois (later King Charles X). In 1816 Richelieu persuaded the king to dissolve the extreme reactionary chamber of deputies (the so-called chambre introuvable) rather than submit to its program. Richelieu resigned in 1818, but returned to power in 1820, after the murder of the duc de Berry caused the fall of Élie Decazes. His measures against the radicals were not sufficient to suit the ultraroyalists, who applied pressure on Louis XVIII and secured (1821) Richelieu's dismissal. With Richelieu's successor, the comte de Villèle, the ultraroyalists came into power.

Richelieu, river, c.75 mi (120 km) long, issuing from the north end of Lake Champlain, near the N.Y.-Que. border, and flowing N across S Que. to the St. Lawrence River at Sorel. It is a link in the waterway connecting the Hudson and St. Lawrence rivers. Visited (1609) by Samuel de Champlain, the French explorer, the river was the route of early explorers. It was an important military corridor in the French and Indian War, in the American Revolution, and in the War of 1812. There are pulp and paper mills along its banks. Ft. Lennox National Historic Park is on Île-aux-Noix near St. Jean, Que.