Schaff, Philip. History of the Christian Church (The Complete Eight Volumes in One). Amazon Kindle Edition, 2014.
Volume 2, Ante-Nicene Christianity A.D. 100-325, “Chapter 12. The Development of Catholic Theology in Conflict with Heresy” Sections 137-158, Loc. 18758-20235.
§ 137. Catholic Orthodoxy.
After a brief bibliography, Schaff states that the theological conflicts of he early Christian period, particularly with the Gnostics, provoked orthodox Christians to respond with assertions and explanations of doctrinal truth (Schaff 2014, Loc. 18763). “From this time forth the distinction between catholic and heretical, orthodoxy and heterodoxy, the faith of the church and dissenting private opinion, became steadily more prominent” (Schaff 2014, Loc. 18773). The idea of catholicity, or universally held truth, was affirmed. In this process, Schaff notes the differences between Greek and Latin patterns of theological orientations also began to emerge. While in the Greek world there was more emphasis on ideas and the more abstract types of knowledge, in the Latin world the teaching tended to point more toward the practical and concrete (Schaff 2014, Loc. 18785). Schaff finds the work of Irenaeus as a strong influence to mediate between East and West. He refutes Gnosticism in no uncertain terms (Schaff 2014, Loc. 18796) even while he makesplain interpretations of ideas such as the Trinity (Schaff 2014, Loc. 18808).
Schaff moves on to describe “heresy” as something which departs from the established opinions. Eventually it took on the additional meaning of pursuing error (Schaff 2014, Loc. 18814). Additionally, for some time Christianity was considered a sect of Judaism, but the term “sect” later came to mean a dissenting minority faction (Schaff 2014, Loc. 18820). By the late 300s, Christians had begun to systematically catalog and categorize heresies and sectarian groups. Although their definition is elusive, the practices of heretics became easier to identify (Schaff 2014, Loc. 18826). Schaff also notes that making theological speculations was not necessarily identified as committing heresy (Schaff 2014, Loc. 18831). On the contrary, Schaff admits that a serious pursuit of orthodoxy could push someone into some kind of bigotry, which would be difficult to overcome. Yet it is necessary to pass on the truth carefully and accurately (Schaff 2014, Loc. 18854).
Schaff notes that the ante-Nicene heresies and the punishments of them differed from those after the Nicene period. First, the early heresies were radical departures from Christianity, held without room for compromise (Schaff 2014, Loc. 18859). The punishment before the Nicene period was entirely churchly, culminating in excommunication, but bearing no civil penalties. After Nicea, some civil penalties tended to be added (Schaff 2014, Loc. 18865).