The apostles and the disciples were empowered by the Holy Spirit and sent to proclaim the Good News all over the world. In Acts 1:8 Jesus said, “But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth.” The apostles started their mission after Pentecost. Each of them went in a different direction. Peter to Antioch and later to Rome, John to Ephesus, Thomas to India, Mark as a disciple went to Egypt and Ethiopia, and St. Paul is known for his apostolic and missionary travels. They established churches and ordained priests. The newborn congregations remained faithful to the apostolic teaching, but never without challenges from outside or even from inside the new churches.
The Monastic movement started in the second or the third century in Egypt with St. Paul of the desert and St. Antony. It started in both Syria and the West in the fourth century.