Inquisition - Medieval Instruments of Torture

To root-out perceived heresy, the Catholic Church began its first Inquisition (especially against Waldensians in southern France) around 1184. The persecution continued, in varying degrees and places (especially in Spain) for about six hundred years.

This documentary, The Catholic Inquisition and The Tools of Torture, provides some background.  Keep in mind that the subject, a gruesome one, means that the video includes sensitive material.