Building on earlier research by the author indicating that the situation which Paul had previously encountered in Antioch was closely related to that facing him in Galatia, in that both involved demands by Jewish Christians that Gentile members of the congregations be circumcised to solve the problem caused by mixed eucharistic table-fellowship, this article develops one aspect of this position by arguing that Peter was actively advocating the circumcision of the Antiochean Gentiles and that this involved a direct breach of the agreement previously reached in Jerusalem (Gal. 2:1-10). It is suggested that much contemporary opposition to this possibility rests upon the anachronistic imposition of modern notions of fair play upon ancient Mediterranean social relations. To avoid this outcome, the author employs a model of social interaction based on the agonistic pattern of challenge and response within the framework of the honour/shame culture as developed recently within the field of Mediterranean anthropology. The model is used to pose a set of new and socially realistic questions to the text. The central issues which emerge in a fresh light using this methodology include: (a) the impact of bringing the uncircumcised Titus into Jerusalem as a provocative challenge to those advocating circumcision of Gentile members of the congregations; (b) the severe shame occasioned to those in Jerusalem who had actively but unsuccessfully sought the circumcision of Titus; (c) an interpretation of the meaning of the agreement in Gal. 2:9 as the declaration of peace after a period of hostility, a peace which consisted of an acknowledgement of the legitimacy of mixed Jewish-Gentile table-fellowship in Paul's communities; (d) pressure motivated by the desire for revenge by those shamed in Jerusalem with respect to Titus as explaining the subsequent change of attitude of James (and Peter); and (e) the meaning of 'Ioin Gal. 2:14 as "to become Jews (through circumcision)," for which there is shown to be ancient support in the commentary of Ambrosiaster.