5–19 March 1179 · Rome
Third Lateran Council
The Third Lateran Council, held by Pope Alexander III in March 1179, introduced the two-thirds majority rule for papal elections and adopted canons on church discipline. It also banned the sale of arms and ship materials to Muslims and granted crusade-like privileges to those fighting “heretics” in southern France.
RESEARCH DOSSIER
Historical analysis of the event
Background
Alexander III had endured a seventeen-year schism with antipopes backed by Emperor Frederick Barbarossa and had been reconciled with the emperor by the Peace of Venice in 1177. With the schism over, the pope held an ecumenical council at the Lateran to restore church order. Among the representatives from the Kingdom of Jerusalem was Archbishop William of Tyre.
The council and its decrees
The council's first canon required that the pope be elected by a two-thirds majority of the cardinals, a rule intended to prevent new schisms. Other canons dealt with matters such as the education of clergy, the ban on holding several church offices and usury.
Two canons matter for the crusades. One threatens with excommunication Christians who sell Muslims arms, iron or ship timber, or who captain their ships. The other grants remission and protection to those who take up arms against the Cathars and similar groups in southern France and the mercenary bands that protect them.
Outcome and significance
The arms-trade ban aimed to limit Italian merchants' continuing trade with Egypt, but it could not be fully enforced and was repeated by later councils. Granting crusade privileges to war against heretics laid the legal ground for the Albigensian Crusade, which would begin in 1209.
The council shows the papacy's growing capacity to define armed movements on different fronts with the same system of privileges.
Sources and debates
The council's canons are published in Tanner's collection. William of Tyre writes that he attended the council and reported on the situation in the East. How effective the arms-trade ban was in practice is debated in light of the Italian cities' commercial records.
Dates, places and figures in this record compare the principal narrative sources with modern scholarship. Where the sources disagree this is stated in the text; for a thesis or publication, consult the relevant edition and page reference.