1. In the third century the question arose for the first time how to treat believers returning to the church from dissident groups. Was the baptism that they had received outside the church valid or not? In North Africa (perhaps under the influence of Tertullian’s De bapt. 15) and also in Asia Minor, synods were held between a.d. 220 and 230 that ruled that heretical baptism was invalid and hence that believers who came over to the church had to receive the church’s baptism (as their first baptism; see Cyprian Ep. 73.3.1, 75.7.5; Eusebius Hist. eccl. 7.5.5, 7.7.5). As regards Rome, t…