Quadragesimo Anno is an encyclical by Pope Pius XI, issued 15 May 1931, 40 years after Rerum Novarum (thus the name, Latin for 'in the fortieth year'). Unlike Leo, who addressed the condition of workers, Pius XI discusses the ethical implications of the social and economic order. Pius XI calls for the reconstruction of the social order based on the principle of solidarity and subsidiarity. He notes major dangers for human freedom and dignity, arising from unrestrained capitalism and totalitarian communism.