Armand Jean du Plessis, cardinal-duc de Richelieu et de Fronsac (French pronunciation: ​[ʁiʃəljø]; 9 September 1585 – 4 December 1642) was a French clergyman, noble and statesman.

Consecrated as a bishop in 1608, he later entered politics, becoming a Secretary of State in 1616. Richelieu soon rose in both the Catholic Church and the French government, becoming a Cardinal in 1622, and King Louis XIII's chief minister in 1624. He remained in office until his death in 1642; he was succeeded by Cardinal Mazarin, whose career he had fostered.

The Cardinal de Richelieu was often known by the title of the King's "Chief Minister" or "First Minister". As a result, he is considered to be the world's first Prime Minister, in the modern sense of the term. He sought to consolidate royal power and crush domestic factions. By restraining the power of the nobility, he transformed France into a strong, centralized state. His chief foreign policy objective was to check the power of the Austro-Spanish Habsburg dynasty, and to ensure French dominance in the Thirty Years' War that engulfed Europe. Although he was a cardinal, he did not hesitate to make alliances with Protestant rulers in attempting to achieve his goals.