Short answer
Yes. Emperors decided the outcome. In 325 the Emperor Constantine called the Council of Nicaea and led it. He was not yet baptised, and he still held the title of high priest of Rome's pagan religion. The bishops (church leaders) declared that the Son is "of one substance" with the Father. Constantine himself urged that word on them. Arius, who taught that the Son was created, was sent into exile. For decades after, councils and emperors swung both ways. In 357 a council even declared the Father greater than the Son. Only in 380 and 381 did the Emperor Theodosius make the Nicene faith the law. Nicaea did not choose the books of the Bible. It fixed a creed (a short statement of belief), and emperors imposed it. Islam's answer is plain: Jesus called the Father the only true God (﷾), and the Qur'an calls people back to that one God (﷾).
Full explanation
The emperor at the council
Constantine called the council and presided over it. Britannica (1971) states that he guided the discussions. It says he personally proposed the key phrase, "of one substance with the Father". Eusebius of Caesarea, a bishop who was there, wrote to his church about it. He said the emperor urged the bishops to accept the word homoousios and explained it himself. Five bishops objected to the word at first, but in the end all but two signed. Britannica says many signed much against their inclination. An order of the emperor sent Arius into exile. Constantine was not baptised until he lay dying in 337.
States that at the Council of Nicaea Constantine himself presided, actively guided the discussions, and personally proposed, no doubt at the prompting of Ossius (Hosius, bishop of Cordoba), the crucial formula of the creed, "of one substance with the Father". It adds that, overawed by the emperor, all but two of the bishops signed the creed, many of them much against their inclination.
Eusebius, bishop of Caesarea, wrote to his church after the Council of Nicaea that the emperor Constantine urged all the bishops to agree to the creed with the insertion of the single word homoousios (of one substance), and explained the word himself. Socrates adds that five bishops at first objected to the word, and that an edict of the emperor sent Arius into exile.
The creed opens: "We believe in one God, the Father Almighty, maker of all things visible and invisible". The council confessed the Son as begotten of the Father, true God of true God, and "of one substance" (homoousios) with the Father, and condemned those who said there was a time when he was not.
Eusebius records that Constantine asked for baptism only when he fell ill and knew he was dying, near Nicomedia in 337, and that he was baptised then, at the end of his life.
Who the emperor was
The man who presided was the head of Rome's old religion as well as its ruler. Like every emperor since Augustus, Constantine held the title pontifex maximus, high priest of the state's pagan cults. He kept it until he died. No emperor gave it up until Gratian in 379. Before his conversion in 312 Constantine had honoured the Unconquered Sun, a Roman sun-god. For years afterwards his coins still showed the sun-god as his "companion". He was baptised only on his deathbed.
Shows that every Roman emperor from Augustus onward held the title pontifex maximus, head of the pontiffs of the state's traditional religion, Constantine and his Christian successors included, and that Gratian was the first emperor to give it up, in 379.
The standard catalogue of Constantine's coins from 313 to 337. It records the coins dedicated "to the Unconquered Sun, companion" (SOLI INVICTO COMITI), still struck for Constantine after his conversion in 312, and dates the sun-god's disappearance from his coinage to about 318-320.
Eusebius records that Constantine asked for baptism only when he fell ill and knew he was dying, near Nicomedia in 337, and that he was baptised then, at the end of his life.
What "of one substance" can and cannot mean
The Greek word homoousios means "of one substance": made of the same stuff. Two copper coins are of the same substance, but that does not make them one coin. So the word by itself says only that the Son shares the Father's nature. It does not explain how two who share a nature are one God. The creed itself begins "We believe in one God, the Father Almighty", naming the one God (﷾) as the Father. Eusebius reports that the emperor explained the word to the bishops himself before they accepted it. Its meaning was argued over for the next fifty years, until the council of 381 fixed it.
The creed opens: "We believe in one God, the Father Almighty, maker of all things visible and invisible". The council confessed the Son as begotten of the Father, true God of true God, and "of one substance" (homoousios) with the Father, and condemned those who said there was a time when he was not.
Eusebius, bishop of Caesarea, wrote to his church after the Council of Nicaea that the emperor Constantine urged all the bishops to agree to the creed with the insertion of the single word homoousios (of one substance), and explained the word himself. Socrates adds that five bishops at first objected to the word, and that an edict of the emperor sent Arius into exile.
A history of the Arian controversy from 318 to 381. Argues that it was not the defence of a settled orthodoxy against heresy, but a search in which the church's doctrine of God was worked out, and reached its final form only in 381.
Arius and what Nicaea condemned
Arius was a priest of Alexandria, a great city in Egypt. He reasoned that if the Father begot the Son, the Son had a beginning. So, he said, there was a time when the Son was not. Nicaea condemned exactly this teaching.
Socrates records the reasoning of Arius, a presbyter of Alexandria: if the Father begot the Son, the Son had a beginning, so there was a time when the Son was not.
Arius, a priest of Alexandria, taught that Christ had a created, finite nature. The Council of Nicaea declared him a heretic in 325 after he refused to sign its formula, and he was exiled. Support from bishops in Asia Minor and from Constantia, Constantine's sister, brought about his return from exile and his readmission to the church. He died in Constantinople in 336, shortly before he was to be reconciled.
The creed opens: "We believe in one God, the Father Almighty, maker of all things visible and invisible". The council confessed the Son as begotten of the Father, true God of true God, and "of one substance" (homoousios) with the Father, and condemned those who said there was a time when he was not.
Fifty years of swinging back and forth, 325 to 381
The creed did not settle the question. The historian R. P. C. Hanson describes the years 318 to 381 as a search for a doctrine, not the defence of one already settled. Here is the record. In 325, at Nicaea, Constantine exiles Arius to Illyria, a Roman province in the Balkans. In 328 he recalls Arius. In 335, after the Council of Tyre, Constantine turns on Athanasius, the bishop of Alexandria who defended the creed. He exiles him to Trier, in Gaul. In 336 the emperor orders that Arius be received back into the church, but Arius dies just before it happens. In 337 the new emperor, Constantine II, sends Athanasius home. In 339 Athanasius flees Alexandria. In 341 two councils at Antioch put out new creeds to stand in place of the Nicene one. In 343, at Sardica, the eastern bishops demand Athanasius's removal. In 346 he is restored. In 351 a council at the city of Sirmium, before the Emperor Constantius, issues another creed without the Nicene word. In 353 and 355 councils at Arles and Milan condemn Athanasius. At Milan, Athanasius records, Constantius told the bishops that whatever he willed was to count as a canon, a church law. In 356 Athanasius is deposed and sent into his third exile. In 357 Sirmium bans the word "substance" as unscriptural. It declares that no one can doubt the Father is greater than the Son. In 359, at Seleucia, a creed calls the Son "like the Father", without saying how. In 361 a council at Antioch declares, as Arius had, that the Son was made from nothing. In all, Athanasius was exiled five times, under four emperors.
Socrates records the swings after Nicaea. Constantine recalled Arius from exile (1.25-26) and later banished Athanasius to Gaul (1.35). A synod at Antioch in 341 put out new creeds that changed the language of the Nicene creed (2.8-10). The Council of Sardica met over Athanasius (2.20). Creeds were published at Sirmium in the presence of the Emperor Constantius (2.30), and a synod met at Milan (2.36). At the synod of Seleucia in 359 Acacius dictated a creed calling the Son like the Father (2.39-40). Soon after, a council at Antioch openly declared, as Arius had, that the Son was altogether unlike the Father and made from nothing (2.45).
Athanasius records that when bishops objected that no church canon allowed what the Emperor Constantius demanded of them, the emperor answered that whatever he willed should be counted as a canon, and told them to obey or be banished.
Arius, a priest of Alexandria, taught that Christ had a created, finite nature. The Council of Nicaea declared him a heretic in 325 after he refused to sign its formula, and he was exiled. Support from bishops in Asia Minor and from Constantia, Constantine's sister, brought about his return from exile and his readmission to the church. He died in Constantinople in 336, shortly before he was to be reconciled.
Athanasius, the leading defender of the Nicene creed, became bishop of Alexandria in 328. After the Council of Tyre condemned him, he appealed to Constantine in person at Constantinople, and Constantine exiled him to Trier in the Rhineland. He was driven out again twice under Constantius II, once under Julian and once under Valens: five exiles under four emperors.
A council of bishops at Sirmium in 357, opposed to the Nicene formula, thirty-two years after Nicaea, ruled that the word "substance" (ousia), and so the Nicene formula "of one substance", should not be used at all, because it is not contained in the divine Scriptures. It also declared that no one can doubt the Father is greater than the Son, quoting Jesus' words "He that sent me is greater than I".
Issued on 27 February 380. The emperors ordered all the peoples under their rule to follow the religion taught by the apostle Peter, and to believe in the one deity of the Father, the Son and the Holy Spirit, in equal majesty and a holy Trinity. Those who refused were to be branded heretics and to face divine punishment and then the emperors' own.
The council confessed the Holy Spirit as the Lord and Giver of life, who proceeds from the Father, and who with the Father and the Son together is worshipped and glorified.
A history of the Arian controversy from 318 to 381. Argues that it was not the defence of a settled orthodoxy against heresy, but a search in which the church's doctrine of God was worked out, and reached its final form only in 381.
- 325
Nicaea
The creed calls the Son “of one substance” with the Father. Constantine exiles Arius, who taught that the Son had a beginning.
- 328–335
The emperor changes sides
Constantine brings Arius back from exile. Then he exiles Athanasius, the creed's great defender, to Trier in Gaul.
- 341–356
Rival creeds
Councils at Antioch and Sirmium put out creeds without the word “of one substance”. Councils at Arles and Milan condemn Athanasius, and in 356 he is sent into his third exile.
- 357
The Father is greater
A council at Sirmium bans the word “substance” and declares the Father greater than the Son.
- 380–381
Another emperor decides
The Emperor Theodosius makes the Nicene faith the law, and the council he called at Constantinople completes the creed.
In all, Athanasius was exiled five times, under four emperors.
How it ended: another emperor
In February 380 the Emperor Theodosius and his co-emperors gave an order. Every people under their rule was to believe in the one deity of the Father, Son and Holy Spirit. All others were threatened as heretics. In 381 the Council of Constantinople, called by Theodosius, restored the Nicene faith and added the clause on the Holy Spirit. The question was closed by imperial law.
Issued on 27 February 380. The emperors ordered all the peoples under their rule to follow the religion taught by the apostle Peter, and to believe in the one deity of the Father, the Son and the Holy Spirit, in equal majesty and a holy Trinity. Those who refused were to be branded heretics and to face divine punishment and then the emperors' own.
The council confessed the Holy Spirit as the Lord and Giver of life, who proceeds from the Father, and who with the Father and the Son together is worshipped and glorified.
What Nicaea did not decide
Nicaea did not choose the books of the New Testament. The earliest surviving list of exactly the twenty-seven books is a letter of Athanasius from 367. Councils in North Africa confirmed the list at the end of the fourth century.
Athanasius, bishop of Alexandria, lists the books he counts as scripture. His New Testament list is the twenty-seven books of today's New Testament, the earliest surviving list of exactly these books and no others.
Traces how the churches came to agree on the New Testament. For three centuries books such as Hebrews, James and Revelation were disputed, and some read the Shepherd of Hermas as scripture. Athanasius' letter of 367 is the first surviving list of exactly the twenty-seven books; councils at Hippo (393) and Carthage (397) confirmed it; the Syrian churches long used a shorter set.
What Christians say about Nicaea
Christians reply that Nicaea did not invent anything. They say the bishops met to defend what the Church already believed against Arius. The creed put that faith into exact words. They point to the opening of John's Gospel, which calls the Word God (﷾).
The creed opens: "We believe in one God, the Father Almighty, maker of all things visible and invisible". The council confessed the Son as begotten of the Father, true God of true God, and "of one substance" (homoousios) with the Father, and condemned those who said there was a time when he was not.
“In the beginning was the Word, and the Word was with God, and the Word was God.”
What Jesus taught, and what the Qur'an says
Jesus called the Father "the only true God" and said, "my Father is greater than I". He warned against teaching the commandments of men as doctrine. The Qur'an tells Christians not to say "Trinity" and to stop going to excess in their religion. It sums up God (﷾) in four short, plain verses.
“And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent.”
“Ye have heard how I said unto you, I go away, and come again unto you. If ye loved me, ye would rejoice, because I said, I go unto the Father: for my Father is greater than I.”
“But in vain they do worship me, teaching for doctrines the commandments of men.”
“O People of the Book! Commit no excesses in your religion: Nor say of Allah aught but the truth. Christ Jesus the son of Mary was (no more than) a messenger of Allah, and His Word, which He bestowed on Mary, and a spirit proceeding from Him: so believe in Allah and His messengers. Say not "Trinity": desist: it will be better for you: for Allah is one Allah: Glory be to Him: (far exalted is He) above having a son. To Him belong all things in the heavens and on earth. And enough is Allah as a Disposer of affairs.”
“They do blaspheme who say: Allah is one of three in a Trinity: for there is no god except One Allah. If they desist not from their word (of blasphemy), verily a grievous penalty will befall the blasphemers among them.”
“Say: He is Allah, the One and Only; Allah, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him.”
The claim and the record
Creed of Nicaea, 325 CE — clause on the Son
The creed opens: "We believe in one God, the Father Almighty, maker of all things visible and invisible". The council confessed the Son as begotten of the Father, true God of true God, and "of one substance" (homoousios) with the Father, and condemned those who said there was a time when he was not.
Cited for
Christians say Nicaea only put into words what the whole Church already believed.
The response
The record shows churches that were not agreed on it. In 357 a council at Sirmium banned the Nicene word itself. It declared that no one can doubt the Father is greater than the Son. In 361 a council at Antioch said the Son was made from nothing. The question was closed in 380 by an imperial order threatening all who disagreed.
Where it lands — The record shows a doctrine fought over and then enforced by law, not one all the churches already held.
Encyclopaedia Britannica (1971), "Constantine"
States that at the Council of Nicaea Constantine himself presided, actively guided the discussions, and personally proposed, no doubt at the prompting of Ossius (Hosius, bishop of Cordoba), the crucial formula of the creed, "of one substance with the Father". It adds that, overawed by the emperor, all but two of the bishops signed the creed, many of them much against their inclination.
Cited for
Some say Constantine only kept order and left the theology to the bishops.
The response
Eusebius, a bishop who was in the room, wrote that the emperor urged the key word on them and explained it himself. Britannica (1971) states that he personally proposed it, prompted by his adviser Bishop Ossius. Either way the word came to the council with the emperor's weight behind it.
Where it lands — The formula of Nicaea came to the bishops through the emperor.
Perspectives
Mainstream Christian
Christians hold that Nicaea defended the faith of the first Christians against a new error. The emperor kept order, but the bishops decided, and the creed says what Scripture teaches.
Christians read John 1:1, which calls the Word God, as the scriptural root of the Nicene creed.
Rebuttal
Grant that John 1:1 calls the Word God (﷾). The same Gospel records Jesus calling the Father "the only true God" and saying "my Father is greater than I". The Qur'an calls Jesus a word from God (﷾) because God (﷾) created him with the word "Be", as He created Adam (3:59). It calls him a messenger and tells Christians not to say "Trinity".
The Islamic perspective
Jesus taught one God (﷾), whom he called the Father, and said the Father was greater than himself. The creed that made the Son equal to God (﷾) goes against his words. The record shows that one emperor brought it to the bishops. It was fought over for fifty years, and another emperor's law finally fixed it.
Constantine presided at Nicaea and urged the bishops to accept the word "of one substance", explaining it himself.
Britannica (1971) states that Constantine personally proposed the formula "of one substance with the Father".
All but two of the bishops signed the creed.
Britannica (1971) judges that the bishops signed overawed by the emperor, many of them against their inclination.
Constantine held the title pontifex maximus, high priest of Rome's pagan religion, while he chaired a council of Christian bishops.
For years after his conversion in 312, Constantine's coins still honoured the Unconquered Sun as his companion.
"Of one substance" does not make two things one. Two copper coins are made of the same substance, and they are still two coins.
The churches were not united on the Nicene faith. For decades after Nicaea, councils backed by emperors issued creeds without its key word.
It was the emperor, not the council, who sent Arius into exile. And Constantine himself was baptised only on his deathbed, in 337.
After Nicaea, Arius was brought back from exile, and the same emperor exiled Athanasius. Later emperors exiled Athanasius again and again.
In 357, thirty-two years after Nicaea, a council at Sirmium banned the Nicene word. It declared that the Father is greater than the Son.
Between 325 and 381 councils swung for and against Nicaea. Antioch in 341 and Sirmium in 351 issued creeds without the Nicene word. Arles and Milan condemned Athanasius. A council at Antioch in 361 declared, as Arius had, that the Son was made from nothing.
Some bishops objected that no rule of the church allowed what he demanded. The Emperor Constantius answered that whatever he wanted should count as a rule of the church.
The matter was settled only when Theodosius made belief in the Trinity the law of the empire in 380. His council finished the creed in 381.
The historian R. P. C. Hanson describes 318 to 381 as a search for a doctrine, not the defence of a settled one.
The creed that makes the Son equal to God (﷾) is not what Jesus taught. He called the Father the only true God (﷾) and said the Father is greater than himself.
The Qur'an tells Christians not to say "Trinity", because Allah (﷾) is one.