This letter is addressed to “the congregations of Galatia.” (Ga 1:2) Apparently, these included congregations in Pisidian Antioch, Iconium, Lystra, and Derbe​—cities of southern Galatia. These congregations were made up of a mixture of Jews and non-Jews, no doubt including Celts, or Gauls.

It seems that the letter was written about 50-52 C.E. This makes it one of the first books of the Christian Greek Scriptures to be completed after the Gospel of Matthew (probably written c. 41 C.E.) and about the same time as 1 and 2 Thessalonians (c. 50 and 51 C.E. respectively). The Galatian congregations were organized about 47-48 C.E. when Paul and Barnabas were on a missionary tour. (Ac 13:1–14:28) About 49 C.E., after the meeting regarding circumcision in Jerusalem, Paul returned to Galatia with Silas. (Ac 15:36–16:6) It was apparently after this, while at another point on his second missionary tour, that Paul received word that some of the Galatian Christians were “turning away” from God. That troubling report prompted him to write this letter of straightforward counsel and strong encouragement. (Ga 1:6; 3:1; 5:7, 8) He may well have written it from Corinth during his 18-month stay (50-52 C.E.), as information would have had time to reach him there from Galatia. Another possible place of writing is Syrian Antioch, where he spent “some time,” apparently in the summer of 52 C.E.​—Ac 18:18-23.

One reason why Paul wrote this letter was to confirm his apostleship. (Ga 1:1; 2:7-9) Also, he counteracted the false teachings of the Judaizers. Those men sought to limit Christian freedom by advocating that it was necessary to adhere to the Mosaic Law, including circumcision and other aspects of Judaism. (Ga 4:17; 6:12, 13) Paul also developed the important theme that a person is declared righteous by faith in Christ Jesus, not by works of law, and that circumcision is therefore unnecessary for Christians. (Ga 2:16, 21; 5:5, 6; 6:15) The letter emphasizes the precious freedom that true Christians attain through Jesus Christ. (Ga 5:1, 13) Paul shows that this freedom encourages faithful ones to be guided by holy spirit and to help one another.​—Ga 5:16, 22-24; 6:1-5.

The letter to the Galatian congregations discloses many facts not found elsewhere about Paul’s life and apostleship.​—Ga 1:1, 13-24; 2:1-14.

Paul says that this letter was written with his “own hand,” possibly meaning that he personally wrote it, unlike his other letters that were penned by secretaries.​—Ga 6:11.

The authenticity of the letter is well-established. Such writers as Irenaeus, Clement of Alexandria, Tertullian, and Origen referred to the letter by name. The Muratorian Fragment, which dates from c. 170 C.E. and is the oldest known list of books of the Christian Greek Scriptures, attributes this letter to Paul. Moreover, the letter is included in the following important Bible manuscripts: the papyrus codex known as P⁴⁶, Codex Sinaiticus, Codex Vaticanus, Codex Alexandrinus, Codex Ephraemi Syri rescriptus, and Codex Claromontanus.