The Second Christian Century
In the first century of the Christian era, the apostles were themselves the witnesses to the birth, teachings, death and resurrection of Jesus, the founders and first teachers of the Christian communities. As the living witnesses began to pass from the scene, a written witness became more important. Writings by the apostles or based directly upon their teachings began to be collected and circulated at a time when there were still enough people alive in the Church who had personal acquaintance with the participants in the events to distinguish true witness from false. The basic decisions had been made by A.D. 130, although the formal and final statement of the New Testament canon did not come until two centuries later.
The writers called since the 17th century the Apostolic Fathers, belonging to the generation immediately following the apostles and who had personal acquaintance with those who had known Jesus, form a bridge of living memory between the first century and the second: St Clement of Rome, of whom St Irenæus of Lyon said, ‘This man, as he had seen the blessed apostles, and had been conversant with them, might be said to have the preaching of the apostles still echoing, and their traditions before his eyes.’ (Adv. Hær. iii, 3); St Ignatius, born in Syria c. 35, martyred c. 110, the successor to St Peter in the see of Antioch; St Polycarp of Smyrna, born c. 70, died c. 155, a disciple of St John the Evangelist; and the anonymous authors of the Didache and the Epistle of Barnabas, composed probably in the last decades of the first century, and the Shepherd of Hermas, composed in Rome about fifty years later.
In the course of the second century, Christian communities continued to spread through the Roman empire, into Gaul and the Roman provinces of Africa (the present Tunisia) and Germania on the left bank of the Rhine. The excellent communications of the Roman world enabled these communities to stay in close touch with each other through visits and letters.
It was also in the second century that the Church was first called upon to recognise and condemn heresy. The first two great heresies were Marcionism and Gnosticism. Related to them was the habit of thought called 'docetism,' the contempt for the physical.