All Pagan religions from the time of Babylon have adopted (in one form or another) a Trinity doctrine or a triad or trinity of gods. Long before the Christian era, numerous variations of the trinity existed, and they were found in a host of pagan religions and mythologies. As with so many other pre-Christian traditional customs and practices, the revival of this doctrine in the Christian era was predictable. It was essential that followers be able to see Christianity – their 'new' religion – in familiar terms.
Triad deities (the worship of a three-in-one god) first appeared in ancient Egypt about three centuries after the Great Flood of Noah's time. These Egyptian deities came to be worshiped as Osiris, Isis and Horus.
After the destruction of the Tower of Babel, Nimrod and his mother-wife Semiramis, the first rulers of Babylon, fled to Egypt. There, Nimrod (known as Ninus or Athothis, among numerous other names) shared rulership with his father Cush (Menes) in the first dynasty. After Nimrod's death, Semiramis claimed his son Horus to have been Nimrod reincarnated. These three – Osiris (Nimrod), Isis (Semiramis) and Horus (the son) – came to be exalted as a triad of deities
There is no evidence the Apostles of Jesus ever heard of a Trinity. The Bible does not teach the doctrine of the Trinity. Neither the word Trinity itself, nor such language as one in three, three in one, one essence or substance or three persons, is biblical language. The language of the doctrine is the language of the ancient Church, taken not from the Bible but from classical Greek philosophy.
Long before the founding of Christianity the idea of a triune god or a god-in-three persons was a common belief in ancient religions. Although many of these religions had many minor deities, they distinctly acknowledged that there was one supreme God who consisted of three persons or essences. The Babylonians used an equilateral triangle to represent this three-in-one god. The Greek triad was composed of Zeus, Athena and Apollo. These three were said by the pagans to 'agree in one.' One of the largest pagan temples built by the Romans was constructed at Ballbek (situated in present day Lebanon) to their Trinity of Jupiter, Mercury and Venus. In Babylon the planet Venus was revered as special and was worshipped as a Trinity consisting of Venus, the moon and the sun. This triad became the Babylonian holy Trinity in the fourteenth century before Christ. Although other religions for thousands of years before Christ was born worshipped a triune god, the Trinity was not a part of Christian dogma and formal documents of the first three centuries after Christ. That there was no formal, established doctrine of the Trinity until the fourth century is a fully documented historical fact. Clearly, historians of church dogma and systematic theologians agree that the idea of a Christian Trinity was not a part of the first century church. The twelve apostles never subscribed to it or received revelation about it. So how then did a Trinitarian doctrine come about? It gradually evolved and gained momentum in late first, second and third centuries as pagans, who had converted to Christianity, brought to Christianity some of their pagan beliefs and practices.
The modern belief in the trinity originated in the 4th century at the Council of Nicaea in approximately 325 C.E. King Constantine, the Roman Emperor and an adherent to paganism, presided over the Council. Its main purpose was to unite the Roman Empire by achieving agreement on Christian doctrine. This would promote a universal consolidation within the church.
As the council proceeded, there were two distinct sides, which the Archdeacon Athanasius of Alexandria, Egypt upheld regarding the trinity. Arius fought for the opposition; but after long weeks of debate, the admitted pagan, Pontifex Maximus Constantine, ruled in favor of the Trinitarian teaching of Athanasius, the Egyptian.
Egypt, one of the oldest civilizations in the world, had long before adopted the pagan belief of the trinity. One of the most famous Egyptian trinities was that of Horus, Isis, and Seb (HIS), a trinity that consisted of father, mother, and son, and a concept that also traces back to Babylonian ancestry.
History teaches that much later, after instituting a mandatory belief in the trinity, Constantine tried to be more tender and merciful with the decision, but it was too late. The Nicene Creed (also known as the Athenasian Creed) had taken hold. All who did not believe in the trinity doctrine were persecuted and killed. Every available instrument of torture was used on the nonbeliever. The Nicene Creed has since been amended, but it is still read today in many of the Protestant and Catholic churches. Those churches that associate themselves with the World Council of Churches now require belief in the trinity doctrine.