The interpretation timeline

The Third Lateran Council

Condemned the Albigenses and Waldenses and issued decrees for the reform of morals.

1179 Rome, the Lateran
Convoked under
Pope Alexander III, Frederick I being emperor
Bishops present
302
What it did
condemned the Albigenses and Waldenses; issued numerous decrees for the reformation of morals

These facts as given by the Catholic Encyclopedia (1913), "Councils" PD

Scholastic

c. 1100 – 1500
1179
A.D.
“Chapter 27. As blessed Leo says, although the discipline of the Church, content with the judgement of a priest, does not carry out bloody punishments, it is nevertheless assisted by the enactments of catholic princes, so that men often seek a salutary remedy while they fear that bodily punishment will come upon them. Therefore, since in Gascony, in the Albigensian territory, in the region of Toulouse and in other places the condemned perversity of the heretics — whom some call Cathars, others Patarenes, others Publicani, others by other names — has so far prevailed that they no longer practise their wickedness in secret, as some do, but make their error known publicly and draw the simple and the weak into agreement with them: we decree that they, and those who defend and harbour them, lie under anathema; and under anathema we forbid anyone to presume to keep or foster them in his houses or on his land, or to carry on trade with them.”
Cap. 27. Sicut ait beatus LEO, licet ecclesiastica disciplina, sacerdotali contenta iudicio, cruentas non efficiat ultiones catholicorum tamen principum constitutionibus adiuvatur, ut saepe quaerant homines salutare remedium, dum corporale super se metuunt evenire supplicium. Eapropter, quia in Gasconia, Albegesio et partibus Tolosanis et aliis locis ita haereticorum quos alii Catharos, alii Patarenos, alii Publicanos, alii aliis nominibus vocant, invaluit damnata perversitas, ut iam non in occulto, sicut aliqui, nequitiam suam exerceant, sed suum errorem publice manifestent et ad suum consensum simplices attrahant et infirmos: eos et defensores et receptatores eorum anathemati decernimus subiacere, et sub anathemate prohibemus, ne quis eos in domibus vel in terra sua tenere vel fovere vel negotiationem cum eis exercere praesumat
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.