In the ancient Church, an encyclical was a circular letter sent to all churches. In the modern Church it is the most authoritative statement a pope can issue on doctrinal or social issues.
Important encyclicals included:
- Pius IX, 1864: Quanta Cura, on religious freedom, liberty of conscience and Church-state relations
- Leo XIII, 1891: Rerum Novarum, on workers’ rights. Supported trades unionism but rejected socialism and defended private property
- Pius XI, 1937: Mit Brennender Sorge (With Burning Anxiety). Condemned Nazism and Nazi treatment of the Catholic Church. One of the few encyclicals not written in Latin. Drafted by the Secretary of