Paul Tillich reinterpreted Christology along the lines of the method of correlation. We need to ask whether this gigantic enterprise has indeed succeeded in preserving Christianity in its original form. I attempt to prove that a significant discrepancy exists between orthodox and Tillichian theology, especially with respect to dealing with the issue of the historical Jesus, the use of ontological concepts and “incarnation”. I therefore set forth the following observations: 1. Tillich mistakenly sets the reality of faith against fides historica and restricts the latter to just one dimensionless point. 2. The ontological concepts employed by Tillich contain contradictions and are unable to adequately express the infinite, qualitative differences between Christ and other human beings. 3. Tillichian Christology misinterprets the dogma of Chalcedon and is a modern, ontological version of Nestorianism.