The Third Lateran Council

Alexander III's election in 1159 had been disputed from the start, and Emperor Frederick Barbarossa backed a rival claimant, launching what became a schism sustained through a succession of four antipopes over nearly two decades of conflict between the papacy and the empire. The Peace of Venice in 1178 brought Frederick to formal reconciliation with Alexander, clearing the way for the council that met the following year to address the disorder the schism had left behind, chiefly the question of how to prevent a divided or disputed election from producing rival claimants again.

The council's answer, Licet de vitanda, required a two thirds majority of the cardinals present for a valid papal election, a threshold high enough that no faction controlling a bare majority could install its own candidate over serious minority objection. The rule displaced the more ambiguous earlier practice, in which acclamation by clergy, nobility and people of Rome had all been claimed at various points as a source of legitimate authority, and it gave the College of Cardinals alone the exclusive right to choose a pope, a change that removed much of the room secular rulers like Frederick had previously found to back a rival candidate of their own.

Canon 27 of the council addressed a problem that would not be resolved by preaching alone: the spread of Cathar and Waldensian belief through Languedoc and neighboring regions of southern France, described in the canon under the general heading of heretics variously known as Cathars, Patarines or by other names. The council authorized secular rulers to seize the property of those who sheltered or supported such groups and offered a partial indulgence, comparable to that granted for pilgrimage to the Holy Land, to those who took up arms against them, a provision that anticipated by exactly thirty years the fuller papal call to crusade Innocent III would issue against the same region in 1209.

The canon's language reflects a church that saw the problem clearly but had not yet developed the institutional machinery, an organized inquisition, to address it directly, relying instead on the cooperation of local lords and bishops who often had their own reasons to tolerate the very communities the council was asking them to suppress. That gap between what the council authorized and what actually happened on the ground in Languedoc over the following decades is part of what made the later, much larger military campaign under Innocent III and Simon de Montfort appear necessary to Rome.