What did the first Christians experience and feel? The first historical psychology of early Christianity. Another major work interpreting early Christianity. One of the most fascinating questions in historiography is the origin of Christianity: What led to the emergence of a movement from a small sect of Judaism that changed world history? To understand this, it is not enough to interpret historical and sociological facts. It is also psychological factors that lie at the root of Christianity. Gerd Theissen illustrates this in his new book. In this psychology of the early Christian religion, the Heidelberg New Testament scholar describes and categorizes the religious behavior and experiences of the first Christians, making it understandable for us today.