Lateran Council, Third, 1179, 11th ecumenical council of the Roman Catholic Church. It was convened at the Lateran Palace, Rome, by Pope Alexander III after the Peace of Venice (1178) had reconciled him with Holy Roman Emperor Frederick I. It was well attended and included an envoy from the Orthodox Greeks. The most important legislation was the first canon, which provided that the election of the pope was thereafter to be in the hands of the cardinals alone, two thirds being necessary for election. The council condemned usury, tournaments, and brigandage. The Albigenses and Waldenses were also condemned. The legislation from this council formed part of the important evolving canonical tradition in the 12th and 13th cent.