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.

Lateran Council, Second, 1139, 10th ecumenical council of the Roman Catholic Church, convened at the Lateran Palace, Rome, by Pope Innocent II. The council attempted to heal the wounds left by the schism of the antipope Anacletus II (d. 1138) and condemned the theories of Arnold of Brescia. Among the council's canons were prohibitions of clerical concubinage and marriage and of the use of bows and crossbows in fighting Christians; simony and usury were also condemned.

Lateran Council, Fourth, 1215, 12th ecumenical council of the Roman Catholic Church, convened at the Lateran Palace, Rome, by Pope Innocent III to crown the work of his pontificate. It was one of the most important councils ever held, and its canons sum up Innocent's ideas for the church. They include a statement of faith with a definition of transubstantiation, confirmation of all kinds of previous disciplinary canons, regulations for the trials of ecclesiastics, arrangements for a new crusade, and many other important matters. This council established the requirements of confession at least once a year and communion at Easter time as the minimum requirement for church membership, called the Easter duty.

Lateran Council, First, 1123, 9th ecumenical council of the Roman Catholic Church, summoned by Pope Calixtus II to signal the end of the investiture controversy by confirming the Concordat of Worms (1122). It was held in the Lateran Palace, Rome, making it the first council to be held in Western Europe. Many of the council's decrees became part of the evolving corpus of medieval Latin canon law.

Lateran Council, Fifth, 1512-17, 18th ecumenical council of the Roman Catholic Church, convened by Pope Julius II and continued by his successor Leo X. Julius called the council to counter an attempt begun (1510) by Louis XII of France to revive the conciliar theory (i.e., that a council has supreme power, even over the pope) of a hundred years before (see Schism, Great) and thus precipitate a new schism. In this maneuver the council was a success. The Concordat of 1516, a papal settlement with France, was ratified there. Otherwise the council accomplished little; the reforming party had to wait until the Council of Trent. It did republish the bull of Julius (1503), which declared that simony invalidated a papal election—a signal reform. Interesting enactments of the council include a decree legalizing the charitable pawnshops the Franciscans had been establishing and another that set up a censorship of printed books.