Macrobe goes farther. He recalls the three Principles to a primitive unit, who is the sovereign God. After resting his theory on this Trinity he adds: "You see how this unit, or original monade of the first cause, is preserved entire and indivisible up to the soul, or spirit, which animates the world." This testimony of Macrobe has so much more bearing, that he wrote in the beginning of the fifth century; that he was the first Chamberlain of the emperor Theodose, and was the most learned antiquarian of that age.
Another most important fact we shall record. It is beyond any doubt that before the coming of Jesus Christ the Jews did not hold the dogma of Trinity, nor do they now. Their Rabbins, and all the Roman Catholic theologians, agree on this point.
During the first three centuries of the Christian era the dogma of Trinity was not generally believed. The Simonians, the Nicholaïtes, the Valentinians, the Basilidians, the Carpocratians, the Ophites, the Sethians, all the Gnostics, and many other Christian sects rejected it. It was only in the fourth century, that Arius and the above sects were condemned in the council of Nice, because they denied the divinity of Jesus Christ. This council was assembled by the order of the emperor Constantine I., who was urged to it by the Bishop of Rome, (or Pope,) whose Church held the dogma of Trinity. As a matter of course the bishops of the council had to decide according to the will of those two leaders; for Constantine threatened them with deposition and exile: in fact he banished Arius, and deposed seventeen bishops, who did not subscribe to the decision of the council.
The doctrine that Jesus Christ was not God himself was so generally spread, and so deeply rooted in the minds, that several successors of Constantine I. embraced Arianism; and it was only after centuries that Arianism, which was spread nearly all over the East, was crushed by the papal and the imperial power.
Now let us draw our conclusions. Since the Jews had no knowledge of the dogma of Trinity, the Church of Rome could not borrow it from them; since the generality of the Christian sects during the first three centuries did not believe in the divinity of Jesus Christ, the Church of Rome did not find the dogma of Trinity in the Gospel; (besides, the Catholic theologians never pretended that the Scriptures teach it—they simply pretended, and still pretend, that it was a tradition.) Since the dogma of Trinity was believed by many Pagan sects, then the Roman Church borrowed it from them.
In turns, the self-called Orthodox Protestant Churches borrowed this doctrine from the Church of Rome, in the sixteenth century.
Therefore the doctrine of Trinity is of Pagan origin.