Final answer:
Peter convinced other Church leaders to welcome Gentiles into the Christian faith, allowing the religion to become universal rather than exclusively Jewish. This aligned with the practices during the reign of Constantine, who enacted the Edict of Milan and facilitated Christianity's legal practice and expansion. Paul also significantly contributed to spreading Christianity among the Gentiles in the ancient world.
Step-by-step explanation:
Peter's role in early Christianity was pivotal in transitioning the religion from a primarily Jewish sect to a more universal religion that welcomed Gentiles (non-Jews) into the faith. According to biblical accounts, particularly in the Acts of the Apostles, Peter had a vision that led him to support the inclusion of Gentiles without requiring them to adhere to traditional Jewish laws.
This was a significant change for the early Church because it opened the door of Christianity to a broader audience, aligning with the view that salvation offered by Christ was for everyone.This decision by Peter and other early Church leaders corresponded with the wider spread of Christianity during the period, notably under the reign of Constantine. Constantine's Edict of Milan, enacted in 313, legalized Christianity and led to a rapid expansion of the Christian population throughout the Roman Empire.
This was facilitated by the apostle Paul, who played a significant role in spreading Christianity among the Gentiles across the Greco-Roman world. Paul's missionary journeys and writings were fundamental in establishing Christian theology and communities in cities such as Ephesus, Corinth, and Rome.