Albigenses, also called Albigensians, the heretics, especially the Catharist heretics, of the 12th-13th-century southern France. The name, apparently given to them at the end of the 12th century, is hardly exact, for the movement centred around Toulouse and in the nearby districts rather than in the city of  Albi (ancient Albiga) itself.  The heresy, which had penetrated into these regions probably by trade routes, came originally from eastern Europe.

It is exceedingly difficult to form any very precise idea of the Albigensian doctrines because present knowledge of them is derived from their opponents and from the very rare and uninformative Albigensian texts that are available.  What  is certain is
that they formed an anti-clerical party in permanent opposition to the Roman Catholic church, and raised a continued protest against the corruption of the clergy of their time.  The Albigensian theologians and ascetics, known in the south of France (Languedoc) as bons hommes or bons chrétiens, were always few in number.

The first Catharist heretics appeared in Limousin (west central France) between 1012 and 1020.  Protected by William IX, duke of Aquitaine, and soon by a great part of the southern nobility, the movement gained ground in the south, and in 1119 the
Council of Toulouse in vain ordered the secular powers to assist the ecclesiastical authority in quelling the heresy.  The people were attached to the bons hommes, whose self-denial and anti-sacerdotal preaching impressed the masses, and the movement maintained vigorous activity for another 100 years, until Pope Innocent III (1198-1216) ascended the papal throne.  At first he tried pacific conversion but at last (1209) ordered the Cistercians to preach the crusade against the Albigenses. Béziers was
laid waste in July 1209 and over 20,000 men, women and children were slaughtered.

Five days after the razing of Béziers, Innocent III wrote Count Raymond VI of Toulouse "From a subject of scandal, you have now become an example to follow; the hand of God appears to have operated marvelously within you." Nearby Narbonne quickly surrended to the vicious crusaders and tried to placate them by offering the crusaders the goods of Narbonne's thriving Jewish community.

This implacable war, the Albigensian Crusade, which threw the whole of the nobility of the north of France against that of the south and destroyed the brilliant Provençal civilization, ended, politically, in the Treaty of Paris (1229), which destroyed the
independence of the princes of the south but did not extinguish the heresy, in spite of the wholesale massacres of heretics during the war.  The Inquisition, however, operating unremittingly in the south at Toulouse, Albi, and other towns during the 13th and 14th centuries, succeeded in crushing it.