The death of Pope Honorius II (February, 1130) was followed by a schism. Petrus Leonis (Pierleoni), under the name of Anacletus II, for a long time held in check the legitimate pope, Innocent II, who was supported by St. Bernard and St. Norbert. In 1135 Innocent II celebrated a Council at Pisa, and his cause gained steadily until, in January, 1138, the death of Anacletus helped largely to solve the difficulty. Nevertheless, to efface the last vestiges of the schism, to condemn various errors and reform abuses among clergy and people Innocent, in the month of April, 1139, convoked, at the Lateran, the tenth ecumenical council. Nearly a thousand prelates, from most of the Christian nations, assisted. The pope opened the council with a discourse, and deposed from their offices those who had been ordained and instituted by the antipope and by his chief partisans, AEgidius of Tusculum and Gerard of Angouleme. As Roger, King of Sicily, a partisan of Anacletus who had been reconciled with Innocent, persisted in maintaining in Southern Italy his schismatical attitude, he was excommunicated. The council likewise condemned the errors of the Petrobrusians and the Henricians, the followers of two active and dangerous heretics, Peter of Bruys and Arnold of Brescia. The council promulgated against these heretics its twenty-third canon, a repetition of the third canon of the Council of Toulouse (1119) against the Manichaeans. Finally, the council drew up measures for the amendment of ecclesiastical morals and discipline that had grown lax during the schism. Twenty-eight canons pertinent to these matters reproduced in great part the decrees of the Council of Reims, in 1131, and the Council of Clermont, in 1130, whose enactments, frequently cited since then under the name of the Lateran Council, acquired thereby increase of authority.

• Canon 4: Injunction to bishops and ecclesiastics not to scandalize anyone by the colours. the shape, or extravagance of their garments, but to clothe themselves in a modest and well-regulated manner.
• Canons 6, 7, 11: Condemnation and repression of marriage and concubinage among priests, deacons, subdeacons, monks, and nuns.
• Canon 10: Excommunication of laymen who fail to Pay the tithes due the bishops, or who do not surrender to the latter the churches of which they retain possession, whether received from bishops, or obtained from princes or other persons.
• Canon 12 fixes the periods and the duration of the Truce of God.
• Canon 14: Prohibition, under pain of deprivation of Christian burial, of jousts and tournaments which jeopardize life.
• Canon 20: Kings and princes are to dispense justice in consultation with the bishops.
• Canon 25: No one must accept a benefice at the hands of a layman.
• Canon 27: Nuns are prohibited from singing the Divine Office in the same choir with monks or canons.
• Canon 28: No church must be left vacant more than three years from the death of the bishop; anathema is pronounced against those (secular) canons who exclude from episcopal election "persons of piety" -- i. e. regular canons or monks.