In 1891, Pope Leo XIII issued 'Rerum Novarum,' a groundbreaking encyclical that addressed social justice issues in the context of industrial capitalism. This document emphasized the rights of workers, the importance of private property, and the role of the state in ensuring social welfare. 'Rerum Novarum' is considered the foundation of modern Catholic social teaching, influencing subsequent papal encyclicals and inspiring movements for social reform and labor rights within the Church and beyond.

Pope Leo XIII's encyclical 'Rerum Novarum', published in 1891, ignited a movement in Catholic social poetry and journalism. Its teachings resonated with figures like Dorothy Day and liberation theology poets in Latin America, influencing a tradition of Catholic social verse that emphasized justice, dignity, and the rights of workers.