The first major period in Christian history is the apostolic age and concerns the rapid expansion of Christianity in the first few centuries. After the death and resurrection of Jesus the faith grew from a very small local group of initially frightened but later dedicated followers, to spreading his teachings throughout the entire Roman empire, Asia minor and beyond. The word apostle means “to send” which was in line with the command to the disciples by Jesus in Matthew 28 to go out and make disciples of all nations, to baptize them in the name of the father son and holy spirit. This is called the Great commission and the aim was to extend his ministry beyond Israel into the wider world.
At the heart of the new Christian movement is a series of reports and interpretations of the words and actions of Jesus which outlined his identity and function. Many of these ideas were drawn from the old Jewish scriptures but were given a new interpretation by Jesus which made them relevant to the wider world. These new ideas formed part of a new covenant that concentrated on the spiritual dimension of the law. Christian groups were formed from those who personally knew Jesus or had heard about him through eye witness accounts. Initially the movement was situated in urban areas such as Jerusalem and consisted mainly of Jews. It was very much a case of Good news travels fast as the Church expanded rapidly in the first few years after the resurrection and this growth is recorded in much detail in the book of Acts. The apostle Peter concentrated his mission in those Jewish areas while Paul of Tarsus became an influential figure in establishing Christian churches in many areas around the Mediterranean Sea.
The book of Acts give accounts of Christians teaching in Syria, Asia minor, Greece and Rome and Christian tradition also speaks of missions in India, Africa and Arabia. Many books in the new testament relate to these Churches. Corinthians (Corinth in Greece) Galatians (Galatia in Turkey) Ephesians (Ephesus in Turkey) Thessalonians (Thessalonica in Greece) Philippians (Philippi in Macedonia) Colossians (Colossae in Turkey) Romans (Rome in Italy ) as well as books relating to Apostles such as Timothy, Titus and Philemon.
The location for the beginning of Christianity is interesting in that it was situated on major trading routes, was part of a vast empire and the areas where the Apostles started Churches were very cosmopolitan attracting traders, travelers and philosophers from many nations, thus allowing the teachings of Jesus to spread more rapidly. Even early in the mission we see the unlikely conversions of Samarians who were seen as unfaithful Jews, the conversion of the Ethiopian Eunuch whose physical condition excluded him from being a Jew and the conversion of the Roman centurion who was required to pledge his allegiance to Caesar and no other.
Paul before his conversion to Christianity had played a huge part in persecuting the early Christian sect but was now fully engaged in spreading the Good news of Jesus Christ as both he and his followers underwent great hardships. They were shipwrecked, beaten and imprisoned for sharing their faith and Stephen who was arrested for blasphemy was stoned to death. Despite opposition and persecution large numbers of people were converted to Christianity as Paul preached to the Gentiles (non-Jews) driving home the idea that the Christian message was for everybody whatever their background.
Distinct ideas developed over a period of time which began to influence their local communities as new Churches were set up all across the Roman empire. Letters were exchanged between the various Christian communities which sought to establish sound teaching many of which became foundational documents forming part of the New Testament and the bible that we know today. These letters cemented key Christian themes around love, faith and trust in God whilst also encouraging Church order. This body of teachings began to be passed down from generation to generation.
This shared and common faith was expressed through a complex network of groups cutting across cultural and language barriers without any overall hierarchical structure. It is remarkable that Christianity spread so rapidly in the first and second centuries through people who were not in it for their own personal gain and traveled long distances to promote the teachings of somebody who was 'no longer' on this earth, including the many who were martyred for remaining faithful to his teachings. It was also during this time that the term Christian was used for the first time at Antioch and is of course still used to this day.
Summary and references Christian History - Alister E McGrath The one stop bible guide - Mike Beaumont