Catholic social teaching is the Catholic doctrines on matters of human dignity and common good in society. The ideas address oppression, the role of the state, subsidiarity, social organization, concern for social justice, and issues of wealth distribution. Its foundations are widely considered to have been laid by Pope Leo XIII's 1891 encyclical letter Rerum novarum, which advocated economic distributism while criticizing both socialism and capitalism (though not market economics per se). Its roots can be traced to the writings of Catholic thinkers such as Thomas Aquinas and Augustine of Hippo, and is also derived from concepts present in the Bible and the cultures of the ancient Near East.
According to Pope Benedict XVI, its purpose "is simply to help purify reason and to contribute, here and now, to the acknowledgment and attainment of what is just. ... has to play her part through rational argument and she has to reawaken the spiritual energy without which justice ... cannot prevail and prosper", According to Pope John Paul II, its foundation "rests on the threefold cornerstones of human dignity, solidarity and subsidiarity".
Catholic social teaching is distinctive in its consistent critiques of modern social and political ideologies both of the left and of the right: liberalism, communism, feminism, atheism, socialism, fascism, capitalism, and Nazism have all been condemned, at least in their pure forms, by several popes since the late nineteenth century.
Catholic social doctrine has always tried to find an equilibrium between respect for human liberty, including the right to private property and subsidiarity, and concern for the whole society, including the weakest and poorest.
The principles of Catholic social teaching, though rooted in the Old Testament custom of the Jubilee, first began to be combined together into a system in the late nineteenth century. Since then, successive popes have added to and developed the church's body of social teaching, principally through the medium of encyclical letters.