Syllabus of Errors

In 1864, Pope Pius IX issued Quanta cura ("with great care") to address and respond to errors and heresies that were prevalent in his day (and today), most of which constitute "modernism" and which were used to attack the Church.

Attached to the document was an appendix, "Syllabus of Errors," which outlined them in specifics, such as

The Syllabus was more a catalog of modern views and papal response to them, with many focused on particular events or trends. It offered nothing new on Catholic doctrine, as it was a response to the present age based on age-old Church doctrine. As his biographer observed,