1. The letter to the Galatians was written by Paul between the years of 54 - 55 A.D. From my reading it does not state where Paul writes the letter from.
2. The audience Paul was writing to were the Gentile Christian churches in Northern Galatia.
3. The three main issues that were discussed in Paul's letter to the Galatians were, do Gentiles have to become Jewish before they can become Christian? Was circumcision necessary for Gentiles who didn't become Jewish before they turned Christian? And is there other Gospels that we can live by?
As Paul was in a very bad mood his answers to these questions were very simply and direct.
Paul strongly believed Gentiles did not have to become Jewish before they can become Christian or had to be circumcised as it is not part of the Gospels and if they did God would not love then any more that someone who didn't.
Paul was deeply offended when the Galatians were slightly changing the Gospel to suit their needs as he believes there is only one Gospel and if you do not believe in it there is no point of being Christian.
4. Paul wrote letters expressing his disgust in the Galatians for changing the gospel to suit their needs. He then told them the way in which to follow Jesus.
He also sent the Hols Spirit and God the father to the churches in Galatia.
He also wrote about Gods infinite faith.