The Trinity

FIRST COUNCIL OF NICAEA (A.D. 325)

The Rise of the Arian Controversy

The First Council of Nicaea met in A.D. 325 in response to the teachings of Arius, a presbyter from Alexandria. Like Origen before him, Arius believed that the Father is greater than the Son, who in turn is greater than the Holy Spirit. Unlike Origen, however, Arius did not believe it possible to have a hierarchy of divine beings. He brought a more radical form of monotheism to Origen’s system and concluded that the Father alone is truly God.

According to Arius, the Son was the One through whom the Father created the universe, yet He was Himself a creature, created ex nihilo (out of nothing). As a creature, the Son was not eternal but had a beginning. As Arius famously declared, “There was when He was not.” Arius further argued that because the Son was begotten, He necessarily came after the Father and, although exalted above every other creature, remained finite and subordinate to the Father.

The Arians appealed to passages such as John 14:28, “The Father is greater than I,“ and Colossians 1:15, “…the firstborn of all creation.“ A similar understanding of Christ’s nature is found today in the teachings of Jehovah’s Witnesses, although their theology is not identical in every respect to that of Arius.

Arius was strongly opposed by his bishop, Alexander of Alexandria, who maintained that the Son was eternally begotten of the Father and therefore fully and truly God. Alexander was supported by his young deacon, Athanasius, while Arius gained the support of several influential eastern bishops, including Eusebius of Nicomedia and others influenced by aspects of Origen’s theological tradition. The controversy rapidly spread throughout the Eastern Church and soon threatened the unity of the Empire itself.

Constantine’s Intervention

When Constantine became sole emperor of both the Eastern and Western Roman Empires in A.D. 324, he found himself forced to intervene. Many refer to Constantine as the first Christian Roman Emperor. While he increasingly favored Christianity following his reported conversion after the Battle of the Milvian Bridge in A.D. 312, historians continue to debate both the sincerity and maturity of his Christian faith. His continued use of Sol Invictus imagery, his delayed baptism until shortly before his death, and aspects of his political and personal conduct—including the executions of his son Crispus and later his wife Fausta—have led many historians to conclude that his religious convictions remained complex and, at times, inconsistent.

Constantine was not a trained theologian, nor does the historical evidence suggest that the theological intricacies surrounding Christ’s deity were his primary concern. Rather, his motives for convening the council appear to have been largely political. He wisely understood that the growing divide within the visible Church threatened its unity, which in turn threatened the stability of an already vulnerable Empire. Consequently, in an effort to restore peace and preserve imperial unity, Constantine convened the Council of Nicaea, which met in June A.D. 325, presiding over it in a political and ceremonial capacity while allowing the bishops themselves to conduct the theological debates.

Some historians have also suggested that Constantine’s favorable disposition toward Christianity may have been influenced, in part, by his increasingly negative attitude toward Judaism. In several of his later writings he referred to the Jews as “the detestable Jewish crowd“ and condemned “the customs of these most wicked,“ reflecting an unfortunate anti-Jewish sentiment that became increasingly common during portions of the fourth century.

The Purpose of the Council

Although the Council of Nicaea is often associated with the doctrine of the Trinity, its primary purpose was not to formulate a complete doctrine of the Trinity but to resolve the controversy surrounding the nature and deity of Jesus Christ. The council sought to establish harmony through a unified confession concerning the Son’s relationship to the Father and to reject the teachings of Arius.

More than three hundred bishops, accompanied by priests, deacons, theologians, philosophers, and imperial officials, attended the council, the vast majority coming from the Eastern provinces of the Empire. While many subjects were discussed, the central question remained remarkably simple: Was the Son created, or was He eternally begotten? Followers of Arius regarded these concepts as essentially equivalent. Alexander and Athanasius insisted they were fundamentally different.

The Challenge of Language

It is also important to understand that many of the theological terms employed during the debates were still developing in meaning. Greek words such as ousia (essence), hypostasis (substance), physis (nature), and prosopon (person) carried a variety of meanings inherited from earlier Greek philosophy, often leading to misunderstanding between Greek and Latin speakers.

Likewise, the distinction between homoousios (“of the same substance”) and homoiousios (“of similar substance”) would become one of the defining issues of the decades following Nicaea. Although differing by only a single Greek letter, the two words represented profoundly different understandings of Christ’s relationship to the Father. The term homoousios was initially viewed with caution by some bishops because of its earlier association with certain Gnostic writings and controversies addressed by the Synods of Antioch (A.D. 264–268). Nevertheless, the council ultimately adopted the term because it most accurately expressed the biblical conviction that the Son fully shares the Father’s divine nature.

Alexander and Athanasius Respond

Alexander and Athanasius argued that begetting belongs eternally to the very nature of the Father. If the Father has eternally existed as Father, then the Son has likewise eternally existed as Son. Thus, Father and Son have always existed together—coeternal, coequal, and consubstantial. The Logos was eternally begotten, not created, and therefore had no beginning. To deny this, they argued, would destroy the unity of the Godhead and make the Son something less than fully God.

Appealing to passages such as John 10:30, “I and the Father are one,” and John 1:1, “The Word was God,” Athanasius became the council’s greatest defender of Christ’s full deity. He argued that the Son must be of the same divine substance (homoousios) as the Father because salvation itself requires it. As Athanasius famously reasoned, “No creature can save a creature.” Only God can save because sin is ultimately an offense against God Himself. The grace revealed through Jesus Christ is therefore the very grace of God, and Christ can fully reveal the Father because He Himself is fully God.

Although Athanasius is rightly remembered as one of the greatest defenders of Nicene Trinitarian theology, others point even earlier to Tertullian of Carthage, who around A.D. 200 became the earliest known Christian writer to use the Latin word Trinitas, from which our English word Trinity is derived.

With Constantine’s support, all but two of the bishops signed the council’s confession, overwhelmingly rejecting Arianism. The resulting statement became known as the Nicene Creed (A.D. 325). It is important not to confuse this original creed with the later Niceno-Constantinopolitan Creed (A.D. 381), which expanded the earlier confession by more fully defining the deity and personhood of the Holy Spirit.

The Nicene Creed (A.D. 325)

We believe in one God, the Father almighty,
maker of all things visible and invisible.
And in one Lord, Jesus Christ, the Son of God,
begotten from the Father, only-begotten,
that is, from the substance of the Father,
God from God, light from light,
true God from true God, begotten not made,
of one substance with the Father,
through Whom all things came into being,
things in heaven and things on earth,
Who because of us men and because of our salvation came down,
and became incarnate and became man, and suffered,
and rose again on the third day, and ascended to the heavens,
and will come to judge the living and dead,
And in the Holy Spirit.
But as for those who say, there was when He was not,
and, before being born He was not,
and that He came into existence out of nothing,
or who assert that the Son of God is of a different hypostasis or substance,
or created, or is subject to alteration or change
– these the Catholic and apostolic Church anathematizes.

The Council of Nicaea (325) intended its creed to serve as the Church’s authoritative confession against Arianism, and the bishops expected it to remain unchanged. However, they did not explicitly declare at Nicaea that the creed itself could never be expanded or amended. That prohibition became more explicit later, particularly at the First Council of Ephesus (A.D. 431), which forbade the composition of another creed to replace the Nicene faith.

The Council of Constantinople (381) did not view itself as replacing the Nicene Creed but as expanding and clarifying it—especially concerning the Holy Spirit—in response to continuing controversies. The resulting creed became known as the Niceno-Constantinopolitan Creed.

THE AFTERMATH OF NICAEA

The Council of Nicaea, often referred to as the first of the ecumenical councils, did not meet with universal acceptance in its own time. Far from ending the debate concerning the deity of Christ, Nicaea actually inaugurated decades of further controversy. 

One significant reason was the council’s adoption of the word homoousios (“of the same substance”). Emperor Constantine strongly advocated for its inclusion in the creed because it was already familiar and acceptable in the Western Church, where Tertullian had earlier described the Trinity as three persons sharing one substance. The term was also generally acceptable to the Antiochene theologians, who strongly emphasized the unity of the Godhead, though they were often less precise in explaining the eternal distinctions between the Father, the Son, and the Holy Spirit.

The situation was very different in the East. Many of the Eastern bishops, particularly those influenced by Origen’s theology, including Eusebius of Nicomedia, viewed the term homoousios with considerable suspicion. They feared that it could be interpreted in one of two undesirable ways. First, it might suggest a materialistic division of the divine substance into three parts. Second, it might open the door to Monarchianism, blurring the eternal distinctions between the Father, the Son, and the Holy Spirit by collapsing them into a single person.

Although many of these bishops ultimately accepted the term and signed the Nicene Creed, they did so more out of political and ecclesiastical necessity than theological conviction. Their signatures did not signify that they had been persuaded by the Nicene arguments. Consequently, the Council of Nicaea did not truly unify the Church. Instead, it effectively divided the Church into two major theological parties whose conflict would continue for more than half a century. Although traditionally called the “Arian Controversy”, the conflict was actually now between the Nicenes and the Origenists. 

until the Council of Constantinople in A.D. 381 more fully clarified and expanded the Church’s Trinitarian confession.

RISE OF EXTREME ARIANISM (350 AD)

Although Constantine had banished Arius to Illyricum for refusing to sign the creed, the controversy was far from over. Many bishops returned to their churches continuing to teach as they had before. Arius himself eventually regained imperial favor, while Athanasius spent much of his ministry defending the Nicene faith and was exiled five separate times because of the continuing political and theological struggle.

During the 350s, an extreme Arian party, later known as the Anomoeans, arose, maintaining that the Son was totally unlike the Father in essence. This extreme position shocked many of the Eastern bishops who had previously been sympathetic to Arius and prompted them to seek greater theological clarity concerning the nature of Jesus Christ.

Athanasius, together with other defenders of the Nicene faith, responded with conciliatory gestures that helped bridge the divide between the Nicene and many of the moderate Eastern bishops. Rather than abandoning either position, a theological formulation gradually emerged that incorporated the legitimate concerns of both traditions. The eternal distinction of the three hypostases—the Father, the Son, and the Holy Spirit—emphasized by Origen and the Eastern theologians, was united with the Nicene affirmation that the three share one divine ousia or homoousios (“substance” or “essence”).

This mediating position was further developed by the Cappadocian Fathers—Basil the Great, Gregory of Nazianzus, and Gregory of Nyssa—whose theological precision helped secure its widespread acceptance. Their work laid the foundation for the Council of Constantinople in A.D. 381, where the Church formally reaffirmed the deity of the Son and more fully defined the deity and personhood of the Holy Spirit, completing what has become known as the Niceno-Constantinopolitan Creed.

THE COUNCIL OF CONSTANTINOPLE (A.D. 381)

In A.D. 381, approximately forty-four years after Constantine’s death, Emperor Theodosius I convened the Council of Constantinople to address the continuing theological disputes surrounding the Trinity and, in particular, the deity and personhood of the Holy Spirit.

The council was initially presided over by Gregory of Nazianzus. However, following considerable political opposition, Gregory resigned. Leadership subsequently passed to Nectarius, who, although not yet baptized and possessing little formal theological training, was elected Bishop of Constantinople and successfully guided the council to its conclusion.

Building upon the theological foundation established at Nicaea, the council clarified and expanded the Church’s confession concerning the Holy Spirit, affirming that He is fully divine and worthy of the same worship and glory as the Father and the Son.

The resulting confession became known as the Niceno-Constantinopolitan Creed, which remains one of the defining creeds of historic Christianity.

The Niceno-Constantinopolitan Creed (A.D. 381)

We believe in one God, the Father Almighty,
Maker of heaven and earth,
and of all things visible and invisible.
And in one Lord Jesus Christ,
the only-begotten Son of God,
begotten of the Father before all worlds,
Light of Light,
very God of very God,
begotten, not made,
being of one substance with the Father;
by whom all things were made.
Who for us men and for our salvation
came down from heaven,
and was incarnate by the Holy Spirit of the Virgin Mary,
and was made man;
and was crucified also for us under Pontius Pilate;
He suffered and was buried;
and the third day He rose again,
according to the Scriptures;
and ascended into heaven,
and sitteth on the right hand of the Father;
and He shall come again with glory
to judge both the living and the dead;
whose kingdom shall have no end.
And in the Holy Spirit,
the Lord and Giver of life,
who proceedeth from the Father;
who with the Father and the Son together
is worshipped and glorified;
who spake by the prophets.
And we believe one holy catholic and apostolic Church.
We acknowledge one baptism
for the remission of sins.
And we look for the resurrection of the dead,
and the life of the world to come.
Amen.

This is the original 381 form of the creed. Many Western churches today recite a slightly different version that includes the Latin phrase Filioque (“and the Son”) in the clause “who proceedeth from the Father and the Son.” That phrase was not part of the creed adopted at Constantinople in 381; it was added centuries later in the Western Church and became one of the principal theological issues contributing to the East–West Schism between Eastern and Western Christianity.

UNANSWERED QUESTIONS REGARDING CHRIST’S NATURE

Although the Council of Constantinople (A.D. 381) had reaffirmed the deity of the Son and formally recognized the full deity and personhood of the Holy Spirit, thereby completing the Church’s classic doctrine of the Trinity, it did not answer every question concerning the person of Jesus Christ. While the Church had now confessed that Christ is truly God, it had yet to fully explain how His divine and human natures were united in the incarnation. Over the next fifty years, this question would become the central theological controversy confronting the Church and would ultimately lead to the First Council of Ephesus in A.D. 431.

FIRST COUNCIL OF EPHESUS (A.D. 431)

Although the Council of Nicaea (A.D. 325) had firmly established the full deity of Jesus Christ by affirming that the Son is of one substance (homoousios) with the Father, and the Council of Constantinople (A.D. 381) had reaffirmed that confession while recognizing the full deity and personhood of the Holy Spirit, significant questions still remained concerning the incarnation. If Jesus Christ is truly God and truly man, then how are His divine and human natures united? Is He one person or two? How should the Church understand the relationship between His deity and His humanity?

These questions came to the forefront through the teaching of Nestorius, who became Patriarch of Constantinople in A.D. 428. Nestorius was deeply concerned with preserving the distinction between Christ’s divine and human natures. He feared that emphasizing their unity too strongly would confuse or mix the two natures, thereby compromising either Christ’s true humanity or His true deity.

The controversy centered upon the title Theotokos, meaning “God-bearer” or “Mother of God,” which had long been used by many Christians to describe the Virgin Mary. Nestorius objected to this title, arguing that Mary did not give birth to the divine nature of Christ but only to His humanity. He therefore preferred the title Christotokos, meaning “Mother of Christ.”

While Nestorius sought to protect the transcendence and immutability of God, many believed his teaching unintentionally divided Christ into two distinct persons—one divine and one human—united only by a close moral or cooperative relationship. If this were true, then the One who suffered upon the cross would not truly be God incarnate but merely a man uniquely associated with God.

Nestorius’ principal opponent was Cyril of Alexandria, one of the most influential theologians of the fifth century. Cyril argued that Scripture presents Jesus Christ as one divine Person who assumed a complete human nature. The eternal Son of God did not merely dwell within a human being or unite Himself to an already existing person; rather, “the Word became flesh” (John 1:14). Therefore, the one born of Mary was none other than the eternal Son Himself clothed in genuine humanity.

For Cyril, the title Theotokos was not primarily a statement about Mary but a confession concerning the identity of Jesus Christ. It did not mean that Mary was the source or origin of Christ’s divine nature, nor that she somehow existed before God. Instead, it affirmed that the child she conceived and bore was truly God the Son incarnate. To deny the title, Cyril believed, was to divide Christ into two persons and undermine the reality of the incarnation itself.

The controversy quickly spread throughout the Empire, dividing bishops, theologians, and entire regions of the Church. Hoping to restore unity, Emperor Theodosius II convened the First Council of Ephesus in A.D. 431.

The council itself was marked by political rivalry and considerable disorder. Bishops arrived at different times, accusations were exchanged between opposing factions, and separate assemblies were even held before all delegates had arrived. Cyril opened the council before the bishops supporting Nestorius reached Ephesus, and after lengthy deliberation the council condemned Nestorius and deposed him from his office. When the Antiochene bishops finally arrived, they convened their own council and, in turn, attempted to depose Cyril. For a time, both sides claimed legitimacy, illustrating how deeply divided the Church had become.

Eventually, Emperor Theodosius II accepted the decisions of the council led by Cyril, although reconciliation between the Alexandrian and Antiochene parties required several more years of negotiation. Nestorius was removed from office and later exiled, while many of his followers established churches beyond the boundaries of the Roman Empire, particularly within Persia and later throughout portions of Asia.

The Council of Ephesus ultimately affirmed that Jesus Christ is one and the same Person, the eternal Son of God, who assumed a complete human nature without ceasing to be fully divine. Consequently, the council upheld the title Theotokos for Mary, not to elevate Mary herself, but to safeguard the biblical truth that the one whom she bore was truly God incarnate. The title was therefore understood as a confession concerning the identity of Christ rather than an exaltation of Mary.

Although the Council of Ephesus successfully rejected what became known as Nestorianism, it did not completely settle the relationship between Christ’s divine and human natures. In reaction against Nestorius, some theologians began emphasizing Christ’s unity so strongly that they appeared to merge His divine and human natures into one. This movement, later associated with Eutyches and commonly called Monophysitism, argued that after the incarnation Christ possessed only one nature.

Thus, while Ephesus clarified who Christ is—one divine Person—it left unanswered how His divine and human natures relate to one another. That question would finally be addressed twenty years later at the Council of Chalcedon (A.D. 451), where the Church confessed that Jesus Christ exists in two complete natures, “without confusion, without change, without division, and without separation.”

The Council of Ephesus therefore serves as the essential bridge between Nicaea and Chalcedon. Nicaea declared that Christ is fully God. Constantinople affirmed the full deity of the Holy Spirit. Ephesus established that Christ is one Person, and Chalcedon completed the Church’s classical Christology by explaining that this one Person possesses two complete natures—fully God and fully man.

Unlawful to Compose New or Different Creed

Unlike the Councils of Nicaea (A.D. 325), Constantinople (A.D. 381), and Chalcedon (A.D. 451), the First Council of Ephesus did not produce a new creed. Instead, the bishops deliberately reaffirmed the Niceno-Constantinopolitan faith and declared that no new or different creed was to be composed or introduced. The council stated:

“It is unlawful for any man to bring forward, or to write, or to compose a different Faith as a rival to that established by the holy Fathers assembled with the Holy Ghost in Nicaea. And those who shall dare to compose a different faith, or to introduce or offer it to persons wishing to turn to the acknowledgment of the truth… if they be bishops or clergymen, let the bishops be deposed and the clergymen deprived of their office; and if they be laymen, let them be anathematized.“

As with most laws, Someone always invents a loophole.

THE INCARNATION THREATENED 

Although the Council of Ephesus (A.D. 431) had successfully affirmed that Jesus Christ is one divine Person and condemned the teachings of Nestorius, it did not fully explain how Christ’s divine and human natures relate to one another within that one Person. In reacting against Nestorius, some theologians moved to the opposite extreme. Rather than separating Christ’s two natures, they so emphasized His unity that they effectively merged His humanity into His divinity. This new controversy, commonly associated with the monk Eutyches and later called Monophysitism, once again threatened the Church’s understanding of the incarnation. Consequently, Emperor Marcian convened the Council of Chalcedon in A.D. 451 to resolve these continuing disputes and to provide a more complete biblical explanation of the person of Jesus Christ.

THE COUNCIL OF CHALCEDON (A.D. 451)

The Council of Chalcedon, convened by Emperor Marcian in A.D. 451, was the fourth ecumenical council of the early Church and is widely regarded as the culmination of more than a century of Christological controversy. While the previous councils had progressively established that Jesus Christ is fully God (Nicaea), affirmed the full deity of the Holy Spirit (Constantinople), and declared that Jesus Christ is one divine Person (Ephesus), an essential question still remained unanswered: How are Christ’s divine and human natures united within that one Person?

The immediate controversy centered upon Eutyches, an elderly monk and archimandrite in Constantinople. In his desire to oppose Nestorianism, Eutyches argued that after the incarnation Christ possessed only one nature. Although he acknowledged that Christ was both divine and human before the incarnation, he maintained that after the union Christ’s humanity had effectively been absorbed into His divinity, much as a drop of vinegar disappears when poured into the ocean. This teaching became known as Monophysitism, from the Greek words meaning “one nature.”

Many church leaders believed that Eutyches had gone too far. If Christ’s humanity had truly been absorbed into His deity, then He could no longer be said to possess a genuine human nature like our own. Such a conclusion threatened the biblical teaching that Jesus experienced true human weakness, temptation, suffering, and death, while remaining without sin. If Christ were not fully human, many argued, He could not truly represent humanity or accomplish humanity’s redemption.

The controversy intensified when Dioscorus, Patriarch of Alexandria and successor to Cyril, strongly defended Eutyches. In A.D. 449, Emperor Theodosius II convened another council at Ephesus to settle the dispute. Rather than restoring peace, however, the council became notorious for intimidation, political coercion, and violence. Eutyches was restored to communion, while many of his opponents—including Flavian, Patriarch of Constantinople—were condemned. Flavian was physically assaulted during the proceedings and died shortly afterward from injuries sustained during the council. Because of these events, Pope Leo I later referred to this assembly as the “Robber Council” (Latrocinium), a name by which it has been remembered throughout history.

Following the death of Emperor Theodosius II in A.D. 450, Marcian became emperor and, together with Pope Leo I, sought to resolve the controversy once and for all. He therefore summoned a new ecumenical council to meet at Chalcedon, near Constantinople, in A.D. 451. More than five hundred bishops attended, making it one of the largest councils of the early Church.

One of the council’s most influential documents was Leo’s Tome, a letter written by Pope Leo I to Flavian several years earlier. Leo carefully explained that Jesus Christ possesses both a complete divine nature and a complete human nature, each retaining its own properties while perfectly united in one Person. The bishops at Chalcedon received Leo’s Tome with great enthusiasm, famously declaring, “Peter has spoken through Leo.”

Building upon the doctrinal foundations laid by Nicaea, Constantinople, and Ephesus, the council adopted what has become known as the Chalcedonian Definition. It affirmed that Jesus Christ is one and the same Son, the eternal Word of God, possessing two complete natures—fully God and fully man.

The council declared that these two natures exist “without confusion, without change, without division, and without separation.” Each phrase was carefully chosen to reject a particular error.

“Without confusion” and “without change” rejected the Monophysite teaching that Christ’s divine and human natures were blended together or that one nature was transformed into the other.

“Without division” and “without separation” rejected the Nestorian tendency to divide Christ into two persons or to separate His divine and human actions as though they belonged to different individuals.

Thus, the council confessed that Christ’s divine nature remained fully divine, His human nature remained fully human, and yet both natures were inseparably united in the one Person of Jesus Christ. His deity neither overwhelmed His humanity nor diminished it. Likewise, His humanity added nothing to His deity nor altered it in any way. Rather, both natures retained their distinct properties while existing in perfect personal union.

This definition preserved the essential truths taught throughout Scripture. Jesus Christ is truly God, able to reveal the Father perfectly and accomplish a salvation that only God Himself could provide. At the same time, He is truly man, able to represent humanity, obey where Adam failed, experience temptation without sin, suffer, die, and rise again as the perfect Mediator between God and man.

Although the Council of Chalcedon became the standard Christological confession for the Roman Catholic Church, the Eastern Orthodox Church, and the majority of later Protestant traditions, not every church accepted its conclusions. Several Eastern churches, particularly those in Egypt, Syria, Armenia, and Ethiopia, rejected Chalcedon’s terminology, believing that it inadequately expressed the unity of Christ’s person. These churches eventually became known collectively as the Oriental Orthodox Churches, and the division that began after Chalcedon has remained one of the oldest enduring schisms within Christianity.

Nevertheless, the Chalcedonian Definition remains one of the most significant theological statements in Church history. Together with the councils of Nicaea, Constantinople, and Ephesus, it completed the Church’s classical understanding of the person of Jesus Christ. Nicaea affirmed that Christ is fully God. Constantinople affirmed the full deity of the Holy Spirit. Ephesus established that Christ is one Person. Chalcedon completed the Church’s Christology by confessing that this one Person exists eternally in two complete natures—fully God and fully man—without confusion, without change, without division, and without separation.

The Chalcedonian Definition (A.D. 451)

Therefore, following the holy Fathers,
we all with one accord teach men to acknowledge one and the same Son, our Lord Jesus Christ,
at once complete in Godhead and complete in manhood,
truly God and truly man,
consisting also of a reasonable soul and body;
of one substance (homoousios) with the Father as regards His Godhead,
and at the same time of one substance (homoousios) with us as regards His manhood;
like us in all respects, apart from sin;
as regards His Godhead, begotten of the Father before the ages,
but yet as regards His manhood begotten, for us men and for our salvation, of Mary the Virgin,
the Mother of God (Theotokos);
one and the same Christ, Son, Lord, Only-begotten,
recognized in two natures, without confusion, without change, without division, without separation;
the distinction of the natures being in no way annulled by the union,
but rather the characteristics of each nature being preserved and coming together to form one Person and one Subsistence,
not as parted or separated into two persons,
but one and the same Son and Only-begotten God the Word, Lord Jesus Christ;
even as the prophets from earliest times spoke of Him,
and our Lord Jesus Christ Himself taught us,
and the Creed of the Fathers has handed down to us.

STILL NO MENTION OF THREE PERSONS

The Nicaea (A.D. 325), Constantinople (A.D. 381), Ephesus (A.D. 431), and Chalcedon (A.D. 451) creeds collectively affirmed that the Father is fully God, that the Son is fully God, that the Holy Spirit is fully God, and that Jesus Christ is one Person possessing two complete natures. However, despite traditional claims to the otherwise, nowhere in these ecumenical creeds is God explicitly described using the now-familiar formula “one God in three persons”. It is simply not there!

ATHANASIAN CREED (580 AD – 700 AD)

Although Tertullian had introduced the language of “three persons, one substance” (tres personae, una substantia) more than a century before Nicaea, the council did not incorporate that terminology into its creed. This is in part because the council’s immediate purpose was to refute Arianism by affirming the full deity of the Son rather than to formulate a comprehensive doctrine of the Trinity. However, it was also in part because the terminology itself was problematic. The Latin words persona and substantia did not translate precisely into the Greek theological vocabulary then in use, and terms such as prosopon, hypostasis, and ousia were still being debated and often understood differently by various bishops. Many feared that speaking of “three persons” might suggest either three separate divine beings or, conversely, merely three modes or roles of one person. Consequently, the council deliberately limited its creed to language upon which broad agreement could be reached.

It was not until the Athanasian Creed, composed sometime later, that the Church gave its fullest classical expression to the doctrine by confessing “one God in Trinity, and Trinity in Unity,”. Although the Athanasian Creed is generally believed to have originated in southern Gaul (modern-day France) during the late fifth or early sixth century, almost certainly not having been written by Athanasius himself, it was not the product of an ecumenical council and therefore did not immediately attain the same universal authority as the Nicene or Constantinopolitan Creeds. Over the following centuries, however, it gained increasing acceptance throughout the Western Church, eventually being received as one of the three great ecumenical creeds during the Reformation and incorporated into the liturgy and confessional standards of numerous Western churches. It is within this creed that the now-familiar formulation of God as “one God in Trinity, and Trinity in Unity,” together with its careful distinction of three Persons sharing one divine substance, receives its fullest classical expression.

The Athanasian Creed

Whosoever will be saved, before all things it is necessary that he hold the catholic faith. Which faith unless every one do keep whole and undefiled, without doubt he shall perish everlastingly. And the catholic faith is this: that we worship one God in Trinity, and Trinity in Unity; neither confounding the Persons, nor dividing the Essence. For there is one Person of the Father; another of the Son; and another of the Holy Ghost. But the Godhead of the Father, of the Son, and of the Holy Ghost, is all one; the Glory equal, the Majesty coeternal. Such as the Father is; such is the Son; and such is the Holy Ghost. The Father uncreated; the Son uncreated; and the Holy Ghost uncreated. The Father infinite; the Son infinite; and the Holy Ghost infinite. The Father eternal; the Son eternal; and the Holy Ghost eternal. And yet they are not three eternals; but one eternal. As also there are not three uncreated; nor three infinites, but one uncreated; and one infinite. So likewise the Father is Almighty; the Son Almighty; and the Holy Ghost Almighty. And yet they are not three Almighties; but one Almighty. So the Father is God; the Son is God; and the Holy Ghost is God. And yet they are not three Gods; but one God. So likewise the Father is Lord; the Son Lord; and the Holy Ghost Lord. And yet not three Lords; but one Lord. For like as we are compelled by the Christian verity; to acknowledge every Person by himself to be God and Lord; So are we forbidden by the catholic religion; to say, There are three Gods, or three Lords. The Father is made of none; neither created, nor begotten. The Son is of the Father alone; not made, nor created; but begotten. The Holy Ghost is of the Father and of the Son; neither made, nor created, nor begotten; but proceeding. So there is one Father, not three Fathers; one Son, not three Sons; one Holy Ghost, not three Holy Ghosts. And in this Trinity none is before, or after another; none is greater, or less than another. But the whole three Persons are coeternal, and coequal. So that in all things, as aforesaid; the Unity in Trinity, and the Trinity in Unity, is to be worshipped. He therefore that will be saved, let him thus think of the Trinity.

Furthermore, it is necessary to everlasting salvation; that he also believe faithfully the Incarnation of our Lord Jesus Christ. For the right Faith is, that we believe and confess; that our Lord Jesus Christ, the Son of God, is God and Man; God, of the Substance [Essence] of the Father; begotten before the worlds; and Man, of the Substance [Essence] of his mother, born in the world. Perfect God; and perfect Man, of a reasonable soul and human flesh subsisting. Equal to the Father, as touching his Godhead; and inferior to the Father as touching his Manhood. Who although he is God and Man; yet he is not two, but one Christ. One; not by conversion of the Godhead into flesh; but by assumption of the Manhood into God. One altogether; not by confusion of Substance [Essence]; but by unity of Person. For as the reasonable soul and flesh is one man; so God and Man is one Christ; Who suffered for our salvation; descended into hell; rose again the third day from the dead. He ascended into heaven, he sitteth on the right hand of God the Father Almighty, from whence he will come to judge the living and the dead. At whose coming all men will rise again with their bodies; And shall give account for their own works. And they that have done good shall go into life everlasting; and they that have done evil, into everlasting fire. This is the catholic faith; which except a man believe truly and firmly, he cannot be saved.