… it seems bizarre that modern people are so dull to the social dangers of religious error. Anyone acquainted with medieval history is aware of the massive civil disorders caused by heretical bodies such as the Cathars, Albigensians, and Waldensians.5 The problems at hand were not, as modern newspaper-readers too readily imagine, mere differences of opinion quietly expressed in polite publications. They were dissensions that tore apart the fabric of society, undermined the family, the political order, individual sanity and responsibility. The Church, or better, Christendom with the Church’s encouragement, was right to act swiftly and, when necessary, severely. Summarizing William Carroll’s account, Fr. William Most brings before our eyes two typical medieval situations:In France and Spain especially, the Cathar heretics were a danger not just to the Church, but to the state, and to all . . . The Cathars then were as dangerous as terrorists today, and brought fear, cruelty, bloodshed and war wherever they had sufficient numbers. In southern France it took the full-armed power of the King of France to overcome them . . . In 1242 the Cathars murdered ten of the Inquisitors.
As to the Spanish episode, the Turks in 1480 attacked the south Italian city of Otranto. 12,000 people were killed, the rest made slaves. The sacred book of Islam does call for killing all “infidels”; the Koran says: “When ye encounter unbelievers, strike off their heads until ye have made a great slaughter among them, and bind them in bonds” (cited from B. Palmer, Understanding the Islamic Explosion, Horizon Books, 1980, p. 36). The Turks killed every cleric in the city and sawed the archbishop in two. So Queen Isabel sent a fleet to Italy. In September of 1480, when it was clear the Turks might do the same to any coastal city, Isabel established the Inquisition. It dealt with the special problem of those who pretended to become Christian, but were not really converted, and might open the gates of the city to the Turks.6