This volume contains selected papers from the broader field of History of Christian Doctrines, and more specifically from Patristics and Reformation studies, but also from the border between them. Most of them were written in the academic year 2014-2015, during my MA studies in the field of Patristics at the Theological University of the (vrijgemaakt) Reformed Churches in the Netherlands, in Kampen. The main topic of the MA programme was the Baptism in the Early Church, therefore the most of these papers presents various aspects of this question.