The City of Antioch: Antioch was located in Syria, on the east coast of the Mediterranean Sea near the border with present day Turkey.
Antioch was a wealthy, cosmopolitan city. It had a population of about 300,00, with about 10% -15% of that being Jewish.
Early Jewish Christians, fleeing from persecution in Jerusalem (Acts 11:19-21), brought Christianity to Antioch. Christianity spread rapidly in Antioch.
When the Jerusalem church learned of the growing church in Antioch, they send Barabas to minister to them and lead them. After a while there was too much for Barabas to do alone, so he went to Tarsus to get Saul, who must had developed a good reputation as a result of his ministry in Tarsus.
Antioch was Paul's base for his missionary journey's and the focal point of Christianity as Christianity spread beyond Judea.