Were early Churcha term translated from the Greek word “Ecclesia” which means an assembly called together and is sometime translated as a congregation. A church is... more fathers who wrote against various heresies of their day. These writings are our main source of information about these early forms of Christianity that have long since disappeared. Irenaeus’s treatise Against HeresiesA five volume book written by Irenaeus, bishop of Lyon, around AD 185 to combat the Gnostic influence in the Church. It sets forth a three part test t... more is the most important book that details the large number and diverse nature of these various groups.