Final answer:
St. Paul's Epistles were written between 50 AD and 60 AD, during which he played a significant role in spreading Christianity throughout the Greco-Roman world and shaping early Christian theology.
Step-by-step explanation:
St. Paul's Epistles were written roughly from 50 AD to 60 AD. As the foremost Christian evangelist, Paul encountered the religious and cultural experience of the Greco-Roman world in cities like Ephesus, Corinth, Thessalonica, and Rome. This engagement was crucial in the spread of Christianity and the formation of Christian doctrine. Paul's conversion from Judaism to Christianity was a significant event, as he began as Saul and, after experiencing a divine revelation on the road to Damascus, began his ministry as Paul. His writings contributed to defining the early Christian movements' understanding that Jesus's crucifixion was a part of a divine plan to absolve human sin.