Fathi on your first article.
The author makes the claim that early Christians did not believe in a triune God. Here are a few quotes by early Christians. All but Ireneaus were alive alongside the Apostles. I would especially like to emphasize Ignatius' quote. That sounds alot like the Trinity.
Polycarp (70-155/160). Bishop of Smyrna. Disciple of John the Apostle.
"O Lord God almighty... I bless you and glorify you through the eternal and heavenly high priest Jesus Christ, your beloved Son, through whom be glory to you, with Him and the Holy Spirit, both now and forever" (n. 14, ed. Funk; PG 5.1040).
Justin Martyr (100?-165?). He was a Christian apologist and martyr.
"For, in the name of God, the Father and Lord of the universe, and of our Savior Jesus Christ, and of the Holy Spirit, they then receive the washing with water" (First Apol., LXI).
Ignatius of Antioch (died 98/117). Bishop of Antioch. He wrote much in defense of Christianity.
"In Christ Jesus our Lord, by whom and with whom be glory and power to the Father with the Holy Spirit for ever" (n. 7; PG 5.988).
"We have also as a Physician the Lord our God Jesus the Christ the only-begotten Son and Word, before time began, but who afterwards became also man, of Mary the virgin. For ‘the Word was made flesh.' Being incorporeal, He was in the body; being impassible, He was in a passable body; being immortal, He was in a mortal body; being life, He became subject to corruption, that He might free our souls from death and corruption, and heal them, and might restore them to health, when they were diseased with ungodliness and wicked lusts." (Alexander Roberts and James Donaldson, eds., The ante-Nicene Fathers, Grand Rapids: Eerdmans, 1975 rpt., Vol. 1, p. 52, Ephesians 7.)
Irenaeus (115-190). As a boy he listened to Polycarp, the disciple of John. He became Bishop of Lyons.
"The Church, though dispersed throughout the whole world, even to the ends of the earth, has received from the apostles and their disciples this faith: ...one God, the Father Almighty, Maker of heaven, and earth, and the sea, and all things that are in them; and in one Christ Jesus, the Son of God, who became incarnate for our salvation; and in the Holy Spirit, who proclaimed through the prophets the dispensations of God, and the advents, and the birth from a virgin, and the passion, and the resurrection from the dead, and the ascension into heaven in the flesh of the beloved Christ Jesus, our Lord, and His manifestation from heaven in the glory of the Father ‘to gather all things in one,' and to raise up anew all flesh of the whole human race, in order that to Christ Jesus, our Lord, and God, and Savior, and King, according to the will of the invisible Father, ‘every knee should bow, of things in heaven, and things in earth, and things under the earth, and that every tongue should confess; to him, and that He should execute just judgment towards all...'" (Against Heresies X.l)
Here is the basis for a three persons God from Scripture. http://www.catholicnewsagency.com/resources/apologetics/trinity/the-trinity-in-scripture/
The author also sets up a straw man by trying to make it look like early Christian councils taught that God was flawed because man is flawed and Jesus became man. This ignores Christian theology. Man was not always flawed. We only became flawed because of disobedience to God. Jesus obeyed God and was free of the corruption from Adams error so he was not flawed and did not make God flawed.
Here are some links on the three councils he mentions and on why they were called, in case you wanted to know more.
He claims the trinity originated in Babylon and moved to Greece and then Christianity. I am not knowledgeable about Babylonian gods so I'm not sure which three he is referring to but in Greece he claims Zeus, Poseidon and Hades were a one God in three persons. This is untrue. The Greeks worshipped those three God's as the most influential among their many gods. They were not believed to be united into one God and in some myths even fought against each other. For example in the Iliad Poseidon supported the Greeks while Zeus supported the Trojans.
The author then quotes Numbers 23:19 out of context. First off the verse is about how God doesn't lie or change like humans. Second, and more importantly, Jesus had not incarnated yet and as such God had not become man.
The author then uses several Christian sources that state the Trinity was not clearly formulated until Nicaea and thus was not believed until then. Here he is incorrect. As I have shown earlier the Trinity was believed by Christians very early in Christian history.
Then he uses the book, The Doctrine of the Trinity Christianity’s Self-Inflicted Wound by Anthony F. Buzzard Charles F. Hunting to claim that the Trinity developed in the 2nd century. The Christians I listed were from the first century and show Mr. Buzzards error.
He then claims that the Trinity was cobbled together from pagan beliefs. Here is an article I found on the subject.
It shows the Church Fathers disdain for paganism.
He then takes a quote by the catholic encyclopedia and twist it to serve his purpose.
Catholic Encyclopedia 1991
"The term 'Trinity' does not appear in scripture"
"(The Doctrine of the Trinity) - hammered out over the course of three centuries of doctrinal controversy against modalism and subordinationism"
He uses this to claim that the Catholic Church made up the trinity. While the word Trinity isn't found in the bible the belief is. Just read the introduction to John's Gospel. Doctrines are attempts to find the correct words to explain a belief. Many incorrect explanations were put forward by people and were refuted under the guidance of the Holy Spirit and declared heretical.
He then repeats his claim on Babylon. Here is a site I found on Babylonian gods and goddesses. I couldn't find any that were a trinity, though I had to skim through it.
He then talks about Arius. Arius claimed that Christ was a created being. However unlike Muslims he did not teach that Jesus was a man but rather a powerful demigod.
The author then attempts to show how Constantine forced the trinity on Christians. I found several articles on Nicaea and his role in it, which I will post below.
Here is an excerpt from the Wikipedia article on Arianism. It shows how Constantine didn't particularly care about the doctrines involved and only wanted agreement from the bishops.
Although he was committed to maintaining what the church had defined at Nicaea, Constantine was also bent on pacifying the situation and eventually became more lenient toward those condemned and exiled at the council. First he allowed Eusebius of Nicomedia, who was a protégé of his sister, and Theognis to return once they had signed an ambiguous statement of faith. The two, and other friends of Arius, worked for Arius' rehabilitation. At the First Synod of Tyre in AD 335, they brought accusations against Athanasius, bishop of Alexandria, the primary opponent of Arius; after this, Constantine had Athanasius banished, since he considered him an impediment to reconciliation. In the same year, the Synod of Jerusalem under Constantine's direction readmitted Arius to communion in AD 336. Arius, however, died on the way to this event in Constantinople. Some scholars suggest that Arius may have been poisoned by his opponents. Eusebius and Theognis remained in the Emperor's favour, and when Constantine, who had been a catechumen much of his adult life, accepted baptism on his deathbed, it was from Eusebius of Nicomedia.
You'll note that after the Council the doctrine of the Trinity was formulated to explain the trifold God found in the Bible and early Church.
In conclusion the idea of a God in three persons was believed since the times of Christ and was shown in the Bible. It was formulated into the doctrine of the Trinity at Nicaea. Note that this doesn't mean that it wasn't believed until then but rather that it was not put into one universal way of explaining it. Before the doctrine of the Trinity there were many ways of explaining the three persons of God. That led to all the disagreements.
Pardon if this is long and full of spelling errors.