Issued by Pope Leo XIII in 1891, Rerum Novarum (“Of New Things”) is the founding document of modern Catholic social teaching. Written amid the upheavals of industrialization, it answered the misery of workers and the rising appeal of socialism with the Church’s own account of justice in economic life.

Leo defended the natural right to private property against socialist proposals to abolish it, while insisting just as firmly that ownership carries grave duties and that workers are owed a living wage, humane conditions, rest, and the freedom to form associations. He rejected the notion that labor is merely a commodity, affirming the dignity of the worker as a person made in God’s image.

The encyclical set out principles that would shape a century of teaching: that the state has a real but limited role in protecting the weak, that employers and workers need one another, and that neither unfettered markets nor state collectivism can secure the common good. It remains the touchstone to which later social encyclicals return.

Read the full text at Vatican.va.