The Syllabus of Errors is the name given to an index document issued by the Holy See under Pope Pius IX on 8 December 1864 at the same time as his encyclical letter Quanta cura.[1] It collected a total of 80 propositions that the Pope considered to be current errors or heresies, pairing the briefest headings with references to the various documents where the actual teachings are found.
The documents referenced by the Syllabus were intended to be a rebuttal of liberalism, modernism, moral relativism, secularization, and the political emancipation of Europe from the tradition of Catholic monarchies[2] but some relate to specific nations.