Rerum novarum, or Rights and Duties of Capital and Labor, is an encyclical issued by Pope Leo XIII on 15 May 1891. It is an open letter, passed to all Catholic patriarchs, primates, archbishops, and bishops, which addressed the condition of the working class. It discusses the relationships and mutual duties between labor and capital, as well as government and its citizens. Of primary concern is the need for poverty amelioration of the working class. It supports the rights of labor to form trade unions, and rejects socialism and laissez-faire capitalism, or unregulated, brutal capitalism, while affirming the right to private property and to a living wage.
A foundational text of modern Catholic social teaching, many of the positions in Rerum novarum are supplemented by later encyclicals, in particular Pius XI's Quadragesimo anno (1931), John XXIII's Mater et magistra (1961), Paul VI's Octogesima adveniens (1971), and John Paul II's Centesimus annus (1991), each of which commemorates an anniversary of the publication of Rerum novarum. It also inspired Catholic activism, and influenced distributists and supporters of corporatism. Socialists generally contest the encyclical's interpretation of socialism, and some socialists, particularly Catholic socialists, interpret Rerum novarum as not rejecting socialism, argue that divine law justifies the abolition of private property, and emphasize its anti-capitalist character.
