The Albigensian Crusade: Christians killing Christians (1209-1229)

The Catholic Church’s crusade against the Cathar heresy took place in the Languedoc region of southern France (centred around the city of Albi, from which the term “Albigensian” derives). This wealthy region had developed a distinct culture and significant autonomy from northern France, with close ties to Aragon and the Mediterranean world.

The Cathars (from the Greek katharoi, meaning “pure ones”) followed a dualistic belief system that significantly departed from Catholic orthodoxy. They believed:

• The material world was evil, created by a malevolent deity (Satan or the “Rex Mundi” – King of the World)
• The spiritual world was good, created by the true God
• Jesus was a purely spiritual being who never truly became human or suffered physically
• Human souls were angels trapped in corrupt physical bodies
• Salvation came through rejecting the material world and breaking the cycle of reincarnation

These beliefs led Cathars to reject Catholic sacraments, especially marriage (as procreation continued the imprisonment of souls in flesh), the Eucharist, and Catholic priesthood. Their ascetic lifestyle—including vegetarianism and rejection of wealth—stood in stark contrast to the perceived corruption of the Catholic clergy.

When Pope Innocent III called for a crusade against the Cathars, northern French nobles eagerly participated, motivated by both religious zeal and the opportunity to seize southern lands. When asked how to distinguish between heretics and true Catholics in the city of Béziers, the papal legate reportedly said, “Kill them all. God will know his own.”

The subsequent massacre claimed thousands of lives, and the decades-long crusade effectively eliminated Catharism through terror, torture, and execution. The campaign established the Dominican Order and the Medieval Inquisition as institutions specifically designed to root out heresy. This violent suppression of alternative Christian interpretations starkly contrasted with Jesus’s teachings of forgiveness and his warnings against judging others.