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1209 CEReputable source · 2 sourcesWell documented

Pope Innocent III authorizes the Albigensian Crusade against the Cathars

The papacy at its most powerful turns armed force against heresy inside Christendom

On the timeline · around 1209 CE · Church, Learning, and LawChurch, Learning, and LawCrisis and CalamityPope Innocent III authorizes the Albigensian Crusade against the Cathars115011751200122512501275

Quick facts

Location
Languedoc, southern France
Called by
Pope Innocent III
Military leader
Simon de Montfort
Duration
1209-1229 CE

What happened

Catharism, a dualist belief system holding that the material world was inherently evil, had spread widely in southern France by the early 13th century, drawing support from nobles, townspeople, and peasants disillusioned with what they saw as the corruption of the Catholic clergy. Pope Innocent III, whose pontificate marked the height of medieval papal authority and who had already summoned rulers and prelates across Europe to his authority, launched the Albigensian Crusade in 1209 after the murder of a papal legate in Cathar territory, the first crusade explicitly aimed at Christian heretics rather than external enemies. Led initially by Simon de Montfort, the campaign continued in on-and-off waves for two decades and, beyond its stated religious purpose, achieved the French crown's political annexation of the independent Languedoc region.

Why it matters

The crusade led directly to the creation of the Medieval Inquisition, a more systematic, argument-based effort to root out heresy through interrogation and conversion rather than battlefield violence, which by the early 14th century had ended Catharism as an organized movement; it also permanently extended direct French royal control over southern France.

How we know

Papal correspondence, the near-contemporary Chanson de la Croisade Albigeoise, and inquisitorial records from the following decades document both the military campaign and the theological investigation that followed it.

Sources

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