This book is called "Galatians" because it is addressed to "the churches in Galatia" (Galatians 1:2, 3:1; I Corinthians 16:1).
From Galatians 1:1 we learn that Paul the apostle was the writer.
Since the date and place of writing are indefinite, we shall not attempt a lengthy discussion of these matters. Scholars have suggested several dates ranging from A.D. 50 to A.D. 58; and three different places of writing: Ephesus, Macedonia and Corinth. We have no data in the epistle indicating the exact date of writing.
Politically it was the Roman province of Central Asia Minor, and included Lycaonia, Isauria and parts of Phrygia and Pisidia. Geographically it was the center of the Celtic tribes. The exact location is a moot question between two schools of thought. Exponents of the South Galatian theory make it include churches founded by Paul on his first mission tour: Antioch, Iconium, Lystra and Derbe (Acts 13:14 to 14:24). The North Galatian school interprets the term to mean a strip of country in the north of Asia Minor, occupied by the Celts. Again, we are more concerned with the contents of the epistle than with exact locations of the ones addressed.
Celtic tribes from Northern Europe invaded Asia Minor about 280 B.C. They were subdued by the Romans in 189 B.C. and incorporated into the Roman province of Galatia in 25 B.C. Galatia means "the land of the Gauls" (Celtae-Galatae-Galli). The people were impulsive, quick-tempered, hospitable and fickle. They received impressions quickly, and just as hastily gave them up. After receiving Paul enthusiastically, they suddenly turned away from him, and from the gospel (1:6-9; Colossians 4:13-15).
The origin of the churches of Galatia is indefinite. As indicated above, some think that the Galatians of this letter were people of Antioch, Iconium, Lystra and Derbe. If so, Paul converted them on his first mission tour (Acts 13,14). However, Acts 16:6 indicates that the term Galatia meant something besides the foregoing places. It has been suggested that Europeans returning home after Pentecost established churches in Galatia. Others think that Paul might have evangelized the country while he was in Tarsus before going to Antioch. At any rate, we know that he visited them on his second tour (Acts 16:6); that he became sick and preached while there (Galatians 4:13-15), and that he also visited them while on his third journey (Acts 18:23).
Paul left the churches running well (Galatians 5:7). Shortly afterwards, Judaizing teachers crept in teaching that the Jewish law was binding upon Christians (Ch. 3). They accepted Jesus as the Messiah, but claimed that salvation is reached through the works of the law, and that Gentiles should be circumcised (5:1-6). In order to carry their point, they tried to undermine Paul's apostolic authority by saying that he was not one of the apostles, and the he received his doctrines from men and not from the Lord (Chs. 1 and 2).
The purpose of the letter was to correct these errors, and show that salvation is a matter of faithful obedience to the gospel of Christ and not to the law of Moses.