St. Alexander the Great

Would Christianity as a world religion exist without Alexander the Great? I wouldn't think so, but Greek culture and philosophy fit well with the Jewish God made manifest in Jesus Christ. After Pentecost, the disciples had a cultural world ready made, on the intellectual level, for their message, and Alexander's conquests had spread that culture throughout the Occident, in the middle of which sat Jerusalem.

From Werner Jaeger's Early Christianity and Greek Paideia:

The Christian historian Johann Gustav Droysen "perceived that without this postclassical evolution of Greek culture the rise of a Christian world-religion would have been impossible."