The Catechism in Questions & Answers

392. Where did the Apostles spread the gospel?

In fulfilment of the Great Commission given them by Jesus Christ—namely to teach and baptise all nations—the Apostles worked in different regions. Apostles Peter and James primarily proclaimed the gospel among the Jews, while Apostles Paul and Barnabas travelled to the Gentile nations of the Mediterranean region. The gospel spread as far as Asia and Africa. Congregations came into being in Egypt, Turkey, Greece, Italy, Libya, Macedonia, Syria, and Cyprus.

The great commission: see Questions 159., 434., 486.