Every person is a unique entity. Because there are billions of people, there are billions of individual perspectives and beliefs. This creates a problem for any organization whose lifeblood is that everybody thinks along the same lines. Almost from the beginning, Christianity has had its share of splinter groups, in-fighting, and outright civil wars. Edward Peters, in Heresy and Authority in Medieval Europe, traces the path of Christian writers who focus their treatises on heretics, sects, and orthodoxy. From Tertullian to John of Brevicoxa, we get nearly one thousand years of church voices on those who seek to disagree.

For some, even believing that you had a choice in the matter branded you a heretic. You either accepted church dogma or you were damned for eternity. People believed that around every corner was someone who could lead your thinking astray, so hyper-vigilance on the matter of church law was par for the course. The separate spreads of Manichaeism, the Cathars, and the Waldensians lead to continuous proclamations of what exactly was orthodox and what wasn’t. Each edict, each papal bull, and each sermon lead to different church philosophies and laws that had to be parsed through, understood, and protected from heretical thought.

Peters’s collection of church writings is an intense look at church history on a single subject. This isn’t a casual read, but sheds a ton of light on a different struggle within the Christian Church. Here, we get not only founding treatises, but also side documents, backstories, and quick histories on many heretical sects. If you’re at all interested in church history, then this one will have a ton of history and original information. Peters tries not comment too much on the treatises, but rather presents them for the reader to digest. A rich and enlightening book. ( )