Go to the powerful and mighty Google and type something like, ” historical background to the book of Galatians” and you will get answers to some of the very important questions above. I clicked on the link www.biblica.com/resources/scholar-notes/niv-study-bible/intro-to-galatians/ about Galatians.
On this page we can see that the Apostle Paul wrote this letter to a few Churches in Galatia in the early 50’s AD.
Galatians 1:2-3– and all the brothers who are with me, To the churches of Galatia: Grace to you and peace from God the Father and our Lord Jesus Christ
Galatians 1:6– I am amazed that you are so quickly deserting Him who called you by the grace of Christ, for a different gospel,
Galatians 1:13-14– For you have heard of my former way of life in Judaism, how I used to persecute the church of God beyond measure and tried to destroy it; 14 and I was advancing in Judaism beyond many of my contemporaries among my countrymen, being more extremely zealous for my ancestral traditions.
But when Cephas came to Antioch, I opposed him to his face, because he stood condemned. 12 For prior to the coming of some men from James, he used to eat with the Gentiles; but when they came, he began to withdraw and separate himself, fearing those from the circumcision.13 The rest of the Jews joined him in hypocrisy, with the result that even Barnabas was carried away by their hypocrisy. 14 But when I saw that they were not straightforward about the truth of the gospel, I said to Cephas in the presence of all, “If you, being a Jew, live like the Gentiles and not like the Jews, how is it that you compel the Gentiles to live like Jews?15 “We are Jews by nature and not sinners from the Gentiles; 16 nevertheless, knowing that a person is not justified by works of the Law but through faith in Christ Jesus, even we have believed in Christ Jesus, so that we may be justified by faith in Christ and not by works of the Law; since by works of the Law no flesh will be justified.