The New Testament is supposedly not historical at all.
According to this very educative article,which debunks the entire theological theories which have been propounded for more than 14 centuries,the Emperor Constantine (Custennyn or Custennin)who lived in the fourth century A.D. authorised the compilation of the New Testament.
As per records, the first ecclesiastical gathering in history was summoned by Constantine and is today known as the Council of Nicaea.The intellectual climate prevailing at the time was woefully puerile.It was that infantile body of men who were responsible for the commencement of a new religion and the theological creation of Jesus Christ.It was at that assembly, and with so many cults represented, that a total of 318 "bishops, priests, deacons, subdeacons, acolytes and exorcists" gathered to debate and decide upon a unified belief system that encompassed only one god.
When the heated debates which went on for nearly one and a half years did not agree upon one god (among the 53 chosen), Constantine ultimately decided upon a new god for them. To involve British factions (since he was of British origin), he ruled that the name of the great Druid god, Hesus, be joined with the Eastern Saviour-god, Krishna (Krishna is Sanskrit for Christ), and thus Hesus Krishna would be the official name of the new Roman god.And because there was no letter "J" in alphabets until around the ninth century, the name subsequently evolved into "Jesus Christ".
Constantine then instructed his deputy to organise the compilation of a uniform collection of new writings developed from primary aspects of the religious texts submitted at the council which collectively came to be known as the Gospels.These compilations went on to become the New Testament.
Constantine died in 337 and his outgrowth of many now-called pagan beliefs into a new religious system brought many converts. Later Church writers made him "the great champion of Christianity" which he gave "legal status as the religion of the Roman Empire"
The Church itself admits that it does not know who wrote its Gospels and Epistles, confessing that all 27 New Testament writings began life anonymously.To sum it up,Christianity is an adaptation of Mithraism welded with the Druidic principles of the Culdees, some Egyptian elements (the pre-Christian Book of Revelation was originally called The Mysteries of Osiris and Isis), Greek philosophy and various aspects of Hinduism.