Rejecting both socialism and unchecked capitalism, with support for private property as well upholding labour rights and the formation of unions, Pope Leo XIII (advocate for workers as well as a flask-carrying aficionado and spokesman for Vin Mariani) this day in 1891 issued the above encyclical—from its incipit (On Revolutionary Change in the World) with the subtitle Rights and Duties of Capital and Labour—which is considered a foundation text of Catholic social teaching and the movement for workers’ justice. Seeing socialist regimes as an encroachment on the church’s role of imparting morality, rather than an ideological system administered by the the state, Leo warned that the seizure of individual possessions and transferring ownership to the community failed to redress the plight of the working-classes and moreover mandating a contract between employees and employers, honest work for honest pay and a dignified livelihood that contributes to class harmony as well as enshrining that jobs be free from unsafe and immoral tasks endangering body soul, privileging the poor over those enjoying a large bounty of temporal blessings.