There was a period of time between Judaism, (Messianic Judaism, Christian-Judaism and, finally,) Christianity in which violent arguments over who/what Jesus was vis a vis deity took place.
One of the reasons for writing down the oral traditions was to solidify certain positions and "prove" a particular opinion by representing those opinions as from a higher source. After all, the Jews were the "people of the book" and no greater authority could be referenced in an argument over orthodoxy than what was "written".
Eventually hundreds (if not thousands) of Messiah stories, Jesus stories were circulated; each with yet more powerful representations of who or what his personage revealed as to nature and importance.
The names of important men became attached to these writings to bolster their authority and authenticity. (The Gospel according to.....)
Eventually.....
What became known as Christianity found an authority to back it up that had some real clout: a Roman Emperor!
The power of the STATE in the person of Constantine (worshipper in the cult of Sol-Invictus, the Sun god) championed Christianity and sought to solidify his constituency by smoothing over differences.
Constantine convoked a Council in Nicene in 325 c.e. for the purpose of working out issues of belief and airing opinions and weeding out troublemakers.
One of the most bitter controversies which seemed irreconcilable concerned the nature of Jesus in regard to his status as a human being or demi-god or deity.
The Roman world was pagan. Rome embraced the religion of Greece. Greece embraced philosophy. The philosophy of Plato and its permutations (known as neo-Platonism) were everywhere well-known. Familiarity with IDEAL FORMS and demi-gods was considered the natural state of existence. Even the emperor himself was often considered to be the son of god and of divine status. How could the leader of the Christian religion be LESS than an emperor???
Jesus, however, was from the religion of Judaism. Judaism was notorious for only having ONE supereme God and no OTHER gods. How could Jesus fit in with Judiac thought and theology if he represented a more pagan realization of theology??
The controversy was a bloody one. Churches were burned, men were beaten and deaths occured over this one issue like no other.
The Roman Empire under Constantine was in a position to settle the matter with the power of the state. It did. Contrary views were punished by violent means and writings were burned which contradicted official views of what was "true".
Eventually the Church which emerged from the Church-State union (Catholic) split within itself over the same argument over the definition of Christ's nature (substance vis a vis the Father) and the Greek Orthodox Church became a rival to the Roman Catholic Church. The Roman Empire split apart into two emperors and two churches for the remainder of the Roman era of domination.
Athanasius and Arius are the two men most often quoted in the argumentations as to the nature of Jesus and his status as deity.
The writings now imputed to be Canon are writings accepted (others being burned) by the same group of arguing bishops and clergy who won the right to excommunicate their opponents.
Depending on the geographical location of a church or congregation; a different theology of Jesus would be preached as True.
The man named Saul who became the most influential self-named Apostle of Jesus, was from a pagan background in the midst of Judaism influenced by neo-Platonism. Paul sought to remove Jesus from Judaism and make his Messianic authority more broad based by appealing to pagans in their familiarity with demi-god status.
As writings about Jesus proliferated a gradual evolution is detected by scholars placing them on a timeline of change. Early writings demonstrate Jesus as human. Later writings color his deeds as superhuman. By the time the Gospel (attributed to John) of John comes along the Jesus represented is now fully on par with the Only True God of the Jews as a morph into equal status without conflict as to number. (Compare Mark with John as to the events in the garden of Gethsemane and the resurrection side by side.)
Jews could no longer accept such a Messiah which violated thousands of years of monotheism. These Jews could have (and did) represented a real holdout to any doctrine of Trinity. However, the Roman army moved against Jewish patriots who were rebellious in Jerusalem. The majority of the Jewish population was dispersed into frightened communities as Rome destroyed the center of worship in Jerusalem. The bulwark against Trinitariansim was sent packing!
This left only the neo-Platonic advocates in a position to widely influence thinking about Jesus and his role as a demi-god/true god.
This status is reflected in John 1:3.
The "truth" of history is written by the winners.