Final answer:
The Pauline Epistles are letters by St. Paul that were influential in the spread of Christianity and in shaping the religion's early doctrines and practices. They highlight the emerging Christian teachings that challenged Roman values, as illustrated by Thecla's story, and helped establish the principles of Christian faith, hope, and love.
Step-by-step explanation:
The Pauline Epistles are a collection of letters written by St. Paul, which played a critical role in the spread of Christianity throughout the Greco-Roman world. These letters, addressed to early Christian communities, confront the religious and cultural norms of cities like Ephesus, Corinth, Thessalonica, and Rome. Through his teachings, Paul dealt with concepts of salvation, divine plan, and living a life in accordance with the teachings of Christ, which were radical and often at odds with traditional Roman values.