For many students of the New Testament, the dating of Galatians is tedious work which does not seem to have much pay-off in reading the book itself. Whether the book is addressed to Northern or Southern Galatia or before or after Acts 15 seems like a pointless question, but it is in fact important since it will influence how we read the conflict between Paul and Peter in Gal 2.
On the one hand, Gal 2:1-10 could refer to the Jerusalem Council (Acts 15). This is in fact a traditional view found in most commentaries. The issue is gentile circumcision and the consensus reached according to Gal 2 is that Gentiles are not required to submit. As I read Polhill (138-139), he seems to lean toward this view, and the fact that he treats Acts 16:1-5 in a section preceding Galatians implies that he is taking the more traditional / majority view. If it this is the case, then Paul writes Galatians in response to a report he has heard from the Galatian churches while he is in Ephesus or Corinth, perhaps in 53, but possibly as late as 57. Assuming the Jerusalem meeting was in 48, this would mean that the Judiazers were still causing problems in Galatia five to ten years after the agreement found in Acts 15.
There are a few problems with the description in Galatians 2. Paul states in Gal 2:1-2 that he took Titus with him to Jerusalem and that the went to Jerusalem in response to a “revelation.” Neither item is mentioned in Acts 15, although Galatians 2:1-2 is not incompatible with Acts 15. In 2:3 we are told Titus was not forced to undergo circumcision, which is more or less the conclusion of the Jerusalem conference. One other minor point, Paul mentions John as a pillar of the community, but Acts does not include John in the discussion. Again, these can still be complimentary descriptions of the same event. Luke is free to describe the events any way he wants to.
On the other hand, Gal 2:1-10 could refer to another incident prior to the Acts 15 conference., perhaps even contributing to the need for the parties involved to meet face to face. In this view, Paul was in Antioch for some time when he went to Jerusalem with Titus to deliver famine relief sent by the church in Antioch (Acts 11:29-30). Paul then does ministry in Galatia and establishes churches in Gentile communities. He then returned to Antioch where he learned that there were people teaching his Gentile converts that they needed to fully convert to Judaism before they were right with God. Paul writes Galatians then goes up to Jerusalem to discuss the matter formally with James.
This view has the advantage of placing the “Antioch incident” of 2:11ff between the first meeting with James and Peter and the Jerusalem council, and chapter two of Galatians is telling the stories chronologically. In fact, the Antioch Incident might be the point of Acts 15:1-2 – Paul and Barnabas encounter people allegedly from James and have “no little dispute with them,” ultimately resulting in the conference of Acts 15. Luke chooses not to record the confrontation with Peter since one of his main theological points is unity in the church.
For me, the fact that Paul never mentions the decision of the in the letter to the Galatians is a persuasive argument against a later date for Galatians. One would imagine that if the Judaizers claimed to be from James, Paul simply had to hold up the letter from the council and say, “Look here, the man you claim as your authority disagrees with you, go back to Jerusalem as get a bit more education on the issue of Gentiles!” That he does not is powerful evidence the council has not yet occurred. It seems best to me, at any rate, to see Galatians as Paul’s response to the Judaizers prior to meeting with James and Peter in Jerusalem.
As many of you know, I am currently infatuated with the ESV Study Bible, and I was please to find that the Galatians notes (written by Simon Gathercole) has the letter written in 48, just prior to the Jerusalem conference.