Our understanding of early Christian beginnings is usually monolithic. It is much determined by the Acts of the Apostles, which pictures a straightforward development from the primitive community in Jerusalem founded on Pentecost to the world-wide mission of Paul climaxing with his arrival in Rome, the political centre of the Greco-Roman world. The Pauline epistles are understood not so much as historical sources reflecting a much more multifaceted early Christian situation fraught with tensions but as theological treatises expounding and defending the doctrine of justification by faith.