The period (beginning c.70 AD and ending c.312 AD) is best characterised as the beginning of the Universal (or Catholic) Church. What is meant by this, is a feeling of unity in the body of believers, rather than a lot of scattered churches believing the same thing. This universal feeling is a result of many factors, each will be looked at in turn.
As we know, Christianity began as an offshoot of Judaism - Jesus was a Jew, as were all the disciples and most of the first converts, and Jesus fulfilled Judaic hopes of a Messiah. The Church stayed centred at Jerusalem (map: J10) initially, with missionaries going out to the surrounding districts. After the fall of Jerusalem in 70 AD, the home of the Church moved to Antioch of Syria (J8).
It soon became apparent that the easiest converts in those early times were Gentile Jews - i.e., those who weren't Jewish by birth yet believed the Jewish Testament (this may be because the evangelists could have preached a message along the lines of: "You can have all that Judaism has to offer and more, and you do not have to be circumcised!" - circumcision was looked down upon by Romans and Greeks). There is evidence that a Church in India was established very early on; it is in fact held by some that the Apostle Thomas started that church.
The central Church soon moved to Rome (E6), and once it settled in, became very influential (this would be expected, as Rome was a very large city). Information on exact movements is unreliable, but it is clear that by the middle of the Second Century, a significant body of believers existed in Gaul (France, C4), obviously others scattered around the Mediterranean; and by end of the Third Century AD in Spain (A6), Britain (C1), North Africa (D8), Cyrene (G10), and Alexandria (I10) (the last of which claims John Mark as their founder).
In short, by the time of the first Christian Roman Emperor (Constantine in 312), no area of the Roman Empire was left without a Christian witness; with the strongest areas of Christian influence being in Syria (J8), North Africa (D8), Asia Minor, Egypt (I12), Rome (E6) and Lyons (D4). It does seem, however, that those who lived in small villages were untouched by the spread of Christianity.
Quite obviously, this remarkable spread in knowledge and acceptance of the gospel is due only to God's grace and His Spirit working amongst the people at the time; but as is the case today, it seems God used human factors such as the burning zeal of the believers and practical expressions of Christian love to work towards His ends. So soon after the death and resurrection of Christ, believers were zealous in their beliefs to the point of mass martyrdom ? - that is, even though there was a great public hatred of Christianity at the time, there were hundreds and thousands of believers (men, women and children) who went willingly to their deaths for their beliefs. The time also saw great expressions of practical Christian love (in the form of caring for others) as well as 'normal' reasons for conversion.
During this period there occurred several government-led persecutions of the Christians. At the time, the Romans and Greeks had a myriad of gods - all for different occasions, fulfilling different purposes. The Roman Government was surprisingly tolerant of other religions (they conquered many other cultures), so long as the people were willing to offer worship to Caesar as well, as by the middle of the Third Century AD, Caesar worship was enforced.
The Jews had always been a problem to the Romans, however, as they would not worship any God but the one true God. Surprisingly, but probably due to the inwardness and seclusion of the Jews, the Romans allowed them an exception. Christians enjoyed this freedom as well until it became clear that they were not just another Jewish sect, but in fact were active in their evangelism and fervent in their refusal to worship Caesar. As a result, they became a serious problem to the Empire and periodic government-led mass persecutions erupted.
Of course the non-Christian people of the Roman Empire participated in this persecution, and did so for many reasons. Most notably, the Christians were different. Believers held a view of the sanctity of marriage, the value of human life and an abhorence of idols - such views went against Roman culture. Also, Christian gatherings seemed secretive to the wider community, and it didn't take much for rumors to spread that the early believers were participating in sexual orgies or cannibalism - the latter was probably a misunderstanding of the nature of the Lord's Supper and eating "Christ's flesh".
At any rate, the above mentioned reasons, coupled with the Christian's absolute zeal and desire to spread the gospel of Christ made them easy scapegoats for anything bad that happened, leading to more persecutions and horrible martyrdoms - Tertullian wrote of the period: "If the Tiber rises as high as the city walls, if the Nile does not send its waters up over the fields, if the heavens give no rain, if there is an earthquake, if there is famine or pestilence, straightaway the cry is, 'Away with the Christians to the lion!'" 1
Previously left unmentioned, we now turn to the beliefs of the Church in this period. The Apostolic period (33-72 AD) could be marked, as far as authoritative teaching is concerned, as an age of epistles - the contents of our New Testament surely attests to that. If a heresy ? erupted in the Church, one or more of the apostles, or disciples of apostles, could write a letter expounding the true doctrine and pointing out the false; and if the heresy persisted, could possibly visit personally.
However, in this age following the apostles, there is a certain lack of institution or clear authority on matters within the church. Of course bishops existed and held a certain authority, but their viewpoints could differ, and their authority was certainly not as clear-cut as that of the apostles. Therefore, when different viewpoints arose concerning theological topics, it fell to those well-read and blessed with the Spirit's guidance to argue for the truth (in what is now called "apologetics"). It was defending the Orthodox ? position against the heretics that led to the forming of a systematic set of beliefs for the Orthodox Church - i.e., when the heretics came out with their false beliefs concerning a subject, the apologists would have to define exactly what Orthodox belief was in that case, and then defend it. It was this process that forced the early Church to clearly state what it believed - that is, what the Bible taught.
Probably the most prominent example of these heresies is to be found in the sect known as Gnosticism. The Gnostics all to some extent believed, similar to the Orthodox, in a supreme God and the need for salvation; but they argued that salvation came by knowledge ("gnosis"), not by faith. To the Gnostics, Christ was not human, and those saved by knowledge were superior to those saved by faith.
The Gnostics were hard to argue against, as they could always fall back on their claim that Christ had come specially to them after His ascension, and given them special knowledge (and this because only they were of the intellectual capacity to handle it); and therefore knew more than the apologists. As a result, an important weapon to defend against these teachings (and the teachings of other heretical groups) was the definition of what good, apostolic? belief was. In fact, it was in response to these types of heresies that the Apostle's Creed was born. (Contrary to the implications of the name, the Apostles didn't compose the creed, and in fact, the Creed as we know it has changed several times.) Its original form, known as "The Old Roman Creed" is found below.
I believe in God Almighty
And in Christ Jesus, his only Son, our Lord
Who was born of the Holy Spirit and the Virgin Mary
Who was crucified under Pontius Pilate and was buried
And the third day rose from the dead
Who ascended into heaven
And sits on the right hand of the Father
Whence he comes to judge the living and the dead.
And in the Holy Ghost
The holy church
The remission of sins
The resurrection of the flesh
The life everlasting.2
Thus while the heretics no doubt confused many, and even pulled some away from the true faith, God used them to spur on the Early Church into a mature growth, with clear teachings and a more organised structure. We also find that the heretics are largely responsible (as far as human responsibility is concerned) for the formation of the New Testament Canon and the subsequent creation of the authoritative body of Scripture: The Bible.
The Bible came down to us in two parts - the Old Testament and the New Testament - and these two parts themselves are made up of several small 'books'; how these books came together to form the Old and New Testaments is the story of the formation of the Old and New Testament Canons?.
The Old Testament (as is accepted by Western Churches today) came to us directly from the Jews - it is a collection of their writings, compiled over millenia and accepted by them as Scripture by 93 AD. Since Christianity is a natural extension of Judaism, it is equally natural that their Scriptures become the Christian Scriptures. (Read more about the formation of the Old Testament Canon here.)
The formation of the New Testament Canon, however, was a more in-depth process for the early Church. The letters and histories that form the NT were written in the latter half of the First Century AD, and soon were associated with each other. The four gospels circulated together certainly by 150 AD, and Paul's letters similarly were collected together and given some degree of authority within the various churches.
Around 150 AD a heretic known as Marcion became prominent, claiming that the ten non-pastoral letters of Paul and the Gospel of Luke alone were authoritative (although he had removed certain parts of the Gospel of Luke!) as he did not like any works which referred to the Jews as God's people. Many today believe that this was the first Canon of Scripture?, although others would disagree. The important point is, that the Church was in a similar situation with the Canon as it was with the Gnostics and heretical teaching - it did not have its own viewpoint on what should constitute a Canon of Scripture... But it needed to.
In that way, heresies such as Marcionism, Montanism and others of the late Second Century greatly encouraged the Church to arrive at a decision concerning which texts were to be considered authoritative - and there were many to choose from! But by the close of the Second Century, all of the twenty-seven texts now included in the Western Protestant Church (Matthew - Revelation) except for Hebrews, James, 2 Peter and 2 & 3 John were generally accepted as authoritative by the various Churches; this based on the acceptance (or lack of) of the authenticity of their authorship.
At this point, it should be made clear that there was still no great structure of the Church at this time - there was no clear line of authority. The way the Church existed was as a number of regional Churches, linked by the common faith in Christ, with different power structures within each but no overseeing authority, except that of Christ. It is probably for this reason that decisions like the contents of the canon, definitions of faith etc. were not settled quickly - they were argued and debated over within the churches and between the churches, until a clear majority was found and a decision could be made.
So by the early Fourth Century AD, not much had changed - Hebrews was held in slightly less doubt, and Jude was now doubted, yet basically the same books were generally accepted as before, and the same books were in doubt as before. We also find that certain other texts were specifically seen as heretical and not to be included in the Canon (some of these later came to form the Apocrypha, which are accepted in the Roman Catholic Church and some others as authoritative).
What caused the doubts over these texts was issues of their inherent authority. Simply put, the Church held that authoritative texts should come from the hand or mind of an Apostle to be authoritative. The Gospels, Acts, Paul's letters, the First Letter of Peter and the First of John were beyond doubt as to authenticity and so these were beyond question. The others, especially Hebrews and 2 Peter, however, were seriously doubted by some.
By 393 AD at the Council of Hippo, these doubts had been put to rest with a combination of convincing the doubters of authenticity, showing that the disputed texts still taught and reinforced Apostolic teaching, and reasoning that they had been upheld in churches and read on Sundays as Scripture for centuries and had not been shown to be harmful. In the end, it came down to choosing those texts which were self-evidently authoritative, and combining them to form the Canon of the New Testament. This decision was then ratified at the Third Council of Carthage in 397 AD, formally accepting also the Jewish Scripture as authoritative Scripture. (Read more about the formation of the New Testament Canon here (PDF).)
Within this period of the Early Church we also find the rise of intellectual Christianity, in the figures of Clement of Alexandria and Origen. Clement of Alexandria was an expert in the Scriptures, in Greek philosophy and in classical literature. Feeling that the gospel was not made attractive to the intellectual Greeks of his time, he taught Orthodox Christianity within an intellectual framework to those who were interested. Many at the time had some understanding of Gnostic thought and other heresies, so he spent considerable time clarifying the true Christian message to his students. It is said that he was particularly gifted at taking up popular themes of discussion at the time, and bringing the discussion down to Christ.
After the turn of the Third Century, persecution forced Clement to flee Alexandria, leaving the gifted 18-year old student Origen (185-254) in control of the school. Origin saw his primary task as teaching and expounding the Bible - which he did with great success, producing quite a library of his own works and achieving great fame. However, although the majority of his works were orthodox and accepted as such, he did go too far in his theology, claiming that eventually all creatures (the devil included) would be reconciled to God. It is predominantly for this reason that he is oft remembered as a heretic.
From our perspective in time, however, it seems fair to suggest that Clement and Origen's work, presenting the gospel to intellectuals, was of the utmost importance to the spread of the gospel - it allowed intellectuals to remain true to the gospel of Christ, and eventually led to the acceptance of Christianity as the official religion of the Roman Empire.
We have previously seen a positive influence of the heretics on the Early Church in the definition of beliefs and the formation of the Bible. However, there were obviously negative impacts as well, and from these we can trace one of the greatest embarrassments of the Church to date: adding to forgiveness through Christ.
By the end of the Second Century, most churches were established under the rule of a single bishop for a region, who had several presbyters under him, who in turn had deacons under them. The deacons ran the local churches, the presbyters talked to new converts, administered the Lord's Supper, maintained discipline and settled disputes etc; and bishops were recognised as the highest human authority of each Church.
In an effort to combat the Gnostic claim of unique and special authority from Christ, as passed down from Gnostic teacher to Gnostic teacher, Irenaeus (in Gaul [C4]) and Tertullian (in North Africa [D8]) suggested that the bishop's position could be traced in an unbroken line from the Apostles, and therefore was of greater authority than the Gnostic teachers. This is the first time that such authority is claimed by the bishops, and it leads down a terrible path.
The Christians of the first two centuries were well-noted for their moral living (seeking to please God) and this in-part could be due to the then-current belief that there were certain sins which would see you expelled from the Church - namely murder, sexual immorality and denial of the faith (although these were still forgivable by God). In the beginning of the Third Century, however, the then-bishop of Rome, Callistus, accepted back adulterers who were repentant, defending these actions with the belief that the Church in Rome was heir to the Apostle Peter who had been given the keys to 'bind and loose the sins of men' by our Lord (Matt. 16:18-19). This was the first time the Roman Catholic Church claimed such unique spiritual authority, and it worried many in other Churches who asked, 'if adulterers are allowed back, why not also those who deny the faith?' (which was effectively saying, 'Next thing you know, they'll even be allowing back people who deny God').
This misgiving was soon shown to be accurate, as a great persecution broke out in 249-251 AD, during which time all in the Roman Empire were forced to declare Caesar as their Lord or face execution. Many Christians died, refusing to deny their faith like this; but many others gave in - some after torture, others after only threats. Once the persecution stopped, however, there was a great deal of believers who had been expelled from the Church for denying their faith who wanted to be received back in - especially considering the popular belief that there was no salvation outside of the Church.
There were two solutions to this dilemma proposed. The first arose out of an increased admiration of martyrs - in many churches, the birthdays of those who died rather than deny their faith were recorded and celebrated at the martyrs' tomb. Some held that the Holy Spirit granted these martyrs special powers of merit, whereby they could cover over others' sins with their excess in merit, thus allowing the forgiveness of those who denied Christ.
The second view, suggested by Cyprian (of Carthage), introduced degrees of guilt, and would allow believers back into the Church if they had only denied their faith under torture. This view was accepted, but unfortunately the idea of degrees of guilt soon took control, and led to a system of penance, whereby a sinner was forgiven after they had spent a certain (prescribed) amount of time feeling sorrow over their sin. Equally unfortunately, the first suggestion was later also incorporated into the Church, in the Roman Catholic doctrine of the Treasury of Merit, allowing merit from a dead saint to cover over the demerits of a sinful believer.
The Church was soon in dispute over these issues, with some (led by Novation) arguing that the Church did not have such power as this. Novation's chief opponent, Cornelius, however, achieved a majority and was elected bishop of Rome. Thus the Catholic Church would now forgive sins based on the ceremony of penance. For such as this was the grace of God in Christ traded.
1 Tertullian, "Apology", ch.40 (jump back to text)
2 The Old Roman Creed cited from Shelley, B, "Church History in Plain Language", p.52. (jump back to text)