To Paul's dismay, the rest of the Jewish Christians in Antioch sided with Peter, including Paul's long-time associate Barnabas: The rest of the Jews joined in this charade and even Barnabas was drawn into the hypocrisy.
This is described as having happened before the death of King Herod (Agrippa) in 44 AD, and thus years before the Council of Jerusalem (dated c. 50).