Hello. Welcome. In this tutorial, we're going to provide a bit of background to the story and emergence of Christianity to help us understand more about the doctrine of the Trinity, the idea that one god can manifest in three distinct persons yet still be considered a unity.
There are many atemporal strands within Christianity. And every century and epic in history has its own non-rational manifestations like this. If there was a first manifestation, an original birth of the timeless, a Christian might say that it was the person of Jesus of Nazareth, an immaculate conception through the Virgin mother, Mary.
His followers were disciples who were committed to his teachings and the belief that he was the Savior, the Son of God, the Jewish Messiah who had been prophesied or foretold in the Hebrew scriptures. He was referred to as Immanuel, which means "God with us." And more often he was called Christ, the Greek word for messiah, or "anointed one." Thus the name, Jesus the Christ, or Jesus Christ.
Followers believe that, as the Son of God, he came to reconcile humankind to God. As God himself in human form, his life, death, and resurrection served to bridge the worlds of the human and the divine. According to the doctrine of original sin, which was elaborated well after his death, he came for the remission of sins to offer everlasting life to all who believed in him as Christ, Lord and Savior.
Most denominations of Christianity today accept the doctrine of the Trinity, which is based on the conception of one god manifested in three distinct persons. God the Father, God the Son, and God the Holy Spirit. These three persons are known as the hypostases.
There was a great deal of controversy over which persons could be considered co-equal and co-substantial with God, especially during the first three centuries of the common era. This was a time when Christianity was a sect of Judaism and there was maybe perhaps some Trinitarian precursors. But the councils of Nicaea and Constantinople in the fourth century were formally the council's that would adopt the Trinitarian doctrine.
Prior to these councils many of the writings of Christian theological concerns were done by early apostolic fathers believed to have contact with the Twelve Apostles. In general, they stayed very close to scripture which, most agreed, did not express the doctrine of the three persons of God. And following this line of belief the school of Arianism developed in the third century based on a priest from Egypt named Arius. And this teaching held that Jesus, although the Son of God, was still subordinate to God, not co-equal, not co-eternal, yet distinct as the formal Trinitarian doctrine would later state later in the fourth century.
This problem of the same yet different just didn't work for many people. However, in the early fourth century, in 325, the first ecumenical council was held in Nicaea which is in present day Turkey. One of the main purposes was to resolve the Arian controversy. And the result was that Arius was condemned as a heretic. And another result of the council was near unanimous agreement on what would become the Nicene Creed, which includes the formal doctrine of the Trinity.
At this first council the issue of Jesus' divinity was agreed upon and then at the Council of Constantinople in 360 the doctrine of the Holy Spirit would be addressed, solidifying the Nicene Creed and the formal, complete, Trinitarian doctrine.
This great mystery of the Christian faith is recognized by most churches, including the Roman Catholic, Eastern Orthodox, Anglican communion, and many, many Protestant denominations as well.
So now let's review and summarize. The doctrine of the Trinity states that God manifests in three distinct persons, God the Father, God the Son, and God the Holy Spirit. These distinct persons are co-equal with, co-substantial and co-eternal with God. Now, this presented a lot of problems in the first several centuries of the common era. And we went through some of those controversies, the Arian controversy which was in fact overturned by the Council of Nicaea and the council of Constantinople. So by the mid to late fourth century of the common era the Nicene Creed was established, which now incorporates the full doctrine of the Trinity as we know it.