Galatians 1:23-24

23 They had only heard people say this about me: ‘At one time, this man caused us to suffer as Christians. He tried to destroy God's message about Jesus. But now he himself is telling people the good news about Jesus.’ 24 When the believers in Judea heard that, they praised God because of me.

1:18Peter was one of Jesus' 12 apostles.
1:21Syria and Cilicia were places north of Israel, south-east of Galatia, near to the Mediterranean Sea.
1:22Judea was the south region of Israel. Jerusalem, the capital city of Israel, was in Judea.