Treatise on Relics

What it is

The Treatise on Relics, written in French by John Calvin in 1543, is a theological book questioning the authenticity of many Christian relics kept in churches and monasteries across Europe. It was published in Geneva and was later placed on the Catholic Church's Index of Forbidden Books.

Why it matters

Calvin lists dozens of relics he considered fake, from multiple bodies of the same saint to implausible objects linked to Jesus and Mary, arguing that such veneration risked idolatry. The treatise shows Calvin's sharp polemical style and his central role in the Reformation's broader attack on Catholic devotional practices.

Look closer

• Why might Calvin have chosen a satirical, listing style rather than a formal theological argument?
• What does his warning about accidentally venerating a thief's or animal's bones tell you about his tone?
• Who would have been offended by this treatise, and who might have found it persuasive?