Papal letters to the Universal Church or, in many cases, especially before Vatican II, to the Bishops in communion with the Holy See. Worthy of special attention besides Rerum Novarum (see previous post) are Quadragesimo Anno, Mater et Magistra, Pacem in Terris, Populorum Progressio, Laborum Exercens, Sollicitudo Rei Socialis, Centesimus Annus, Caritas in Veritate, Fides et Ratio, and Spe Salvi. As of this post, the Vatican has online the encyclicals of Leo XIII, Pius X, Benedict XV, Pius XI, Pius XII, John XXIII, Paul VI, John Paul II, Benedict XVI, and Francis. ISBN recommendation: 0-87650-259-1
A joint Catholic-Orthodox declaration, proclaimed 7 December 1965, committing the excommunications, related to Papal embassy to Constantinople in 1054, to oblivion. The declaration marks a first step toward reconciliation between the Catholic and Orthodox communions. Image links to Vatican translation.
Considered by the Holy See an ecumenical council, Vatican II (A.D. 1962-65), was summoned by Pope John XXIII and begins a new phase in the development of the Church. The Council sought to initiate the adaptation of the Church to the modern world – presenting Christ as the relevant Truth even in the present age. Image above links to the Vatican translations of the Council decrees. ISBN recommendation: 0-87840-490-2