Has Christianity strayed too far from its origins? Is its history one of decline and decadence in the sense of secularization, making 'de-secularization' more urgent than ever? Franz Dünzl aims to trace the early Christian shift in mentality, which does not begin with the so-called 'Constantinian Turn' but rather breaks ground in the first centuries, with its earliest traces already found in the New Testament. This volume outlines the development from its beginnings to the 4th century, plausibly describes its dynamics, and identifies reasons why Christianity has been situated from the very start in the tension between world distance and world responsibility, unable to abandon either of these two poles.