Anthony N. S. Lane
In tackling this theme we will consider first the sources that are available to us concerning the Council of Nicaea, secondly the purpose for the calling of the council (looking especially at the events which led up to the council), thirdly the events of the council itself, fourthly the official documents of the council (creed canons and letter) and fifthly related letters written concerning the council. Finally we shall review this material in order to draw together some conclusions concerning the purposes and themes of the council.
If any official minutes, or Acta, were kept of the Council of Nicaea, these have not survived. But fortunately, that does not mean that we are left in the dark. There are four different types of documents on which we can rely.
First, although there are no minutes, the Creed of the council and its twenty canons, or disciplinary decisions, are preserved in a variety of sources, as is a synodical letter that the council sent to the church of Alexandria. 
Secondly, the council is described in a number of church histories from the period. Eusebius of Caesarea, the first church historian, concludes his famous Church History before the time of the council, but he does cover the events in his later Life of Constantine.  From the following century there are three important church histories which pick up from where Eusebius left off and which all, at or near the beginning, cover the events of Nicaea. These are by Socrates, Sozomen and Theodoret,  all of whom wrote in the 440s. Although they were writing more than a hundred years after the event, they were using contemporary documents, for which they are valuable sources.
Thirdly, although there are no minutes, three of those who were present and deeply involved in events later describe the council. Eusebius of Caesarea’s Life of Constantine, already mentioned, covers the council but completely ignores the theological issues at stake.  He does, however, describe the doctrinal discussions in an important letter to his church justifying his own behaviour at the council.  Athanasius also describes the events of the council in two of his later works.  Finally, Eustathius of Antioch’s account is preserved by Theodoret in his Church History.  As Eusebius and Eustathius were bitterly opposed to one another their two rival partisan accounts are valuable for reconstructing the course of the debate.
Finally, there are a few other documents which have survived independently of the above, such as the letter from the earlier Council of Antioch and Constantine’s letter naming Nicaea as the venue for our council.
Why was there a Council of Nicaea? The sources are clear that the Emperor Constantine called the council in order to bring an end to dissension within the church. In particular, he was concerned about two specific issues which were causing disagreement: Arianism and the date of Easter.  Other matters were settled at the council, but these were the two that prompted the calling of the council.
Since the second century there had been rival ways of calculating the date of Easter.  Such diversity was tolerable in the pre-imperial persecuted church. It was not tolerable for the new Christian emperor and his imperial church. Constantine was influenced by the old pagan idea of the pax deorum, the idea that the purpose of the state religion was to win the favour of the gods by offering them acceptable worship. Their side of the deal was to bring peace and prosperity to the empire. Constantine the Christian held to a Christianised version of this. It was his duty as emperor to ensure that the Christian God received pure worship from a harmonious and undivided church. Internal harmony is always a greater priority for the politician than the theologian and this was especially true where Constantine was concerned. For the emperor, the primary scandal with Arianism and the diverse dates of Easter was not the fact of error but the fact of division. 
The question of the date of Easter needs no further elaboration, but the Arian controversy is more complex. A brief review of the events leading to the council is in order. While the precise dating and order of some of the events is uncertain, what actually happened is clear enough, which is all that is necessary for our purposes. 
Some time around AD 318/9 Alexander, bishop of Alexandria, was told about the unorthodox views of Arius, an influential presbyter in the same church. These views concerned the deity of Christ. Here is not the place for a full discussion of Arius’s views or their origin, about which there has been considerable discussion in recent years.  Fortunately, there is no serious question about the basic thrust of Arius’s teaching, which is all that needs concern us at present. Arius himself very accurately stated the issue in a letter to Eusebius of Nicomedia, a leading bishop who supported him:
We are persecuted, because we say that the Son has a beginning, but that God is without beginning. This is the cause of our persecution, and likewise, because we say that he is of the non-existent. And this we say, because he is neither part of God, nor of any essential being. 
The two debated points were whether or not the Son had a beginning and whether or not he was created out of nothing. Behind these is the fundamental issue of the deity of Christ, which Arius denied. For him the Son was not to be identified with God himself but is the first and greatest of God’s creatures. He was made ex nihilo, although Arius (like the Jehovah’s Witnesses today) also affirmed that all of the rest of God’s creation was made through the Son. Since time is an aspect of the created universe, which was made through the Son, the latter existed before all time.  But he is not eternal and ‘before his generation he was not.’ The same idea was also expressed in the Arian slogan ‘there was once [before time] when he was not’—~jn pote “ote ohuk ~jn. These are the key points, to which Nicaea responded. Arius was also accused of teaching that the Son was morally mutable and liable to sin and change,  that he is called God’s Word and Wisdom only loosely or inaccurately as courtesy titles  and that he has no perfect or even direct knowledge of the Father.  The first of these is the charge most often repeated and is answered in the Creed of Nicaea.
Alexander took action against Arius, calling a synod of bishops and requiring him to sign a confession of orthodoxy. Arius declined to do so and was excommunicated. Arius and his supporters travelled, seeking and gaining support. Alexander responded by sending out an encyclical letter to all bishops.  A council was held in Bithynia which declared Arius orthodox and demanded his restoration by Alexander. Arius also wrote a conciliatory letter to Alexander, with a manifesto of his beliefs.  Arius received support from Eusebius of Caesarea and from a council of Palestinian bishops, which protested to Alexander about his treatment of Arius and in turn received a stern reply. Arius thereupon wrote a letter to another Eusebius, bishop of Nicomedia,  whose influence was then considerable since Nicomedia had become the site of an imperial palace. ‘When Eusebius received the epistle, he too vomited forth his own impiety,’ and wrote an important letter to a like-minded bishop, Paulinus of Tyre. 
At this point the situation was transformed. Since 312 the western empire had been ruled by the newly converted Constantine, the eastern half by the pagan Licinius. Relations between the two had deteriorated and Licinius began to oppress the church in his domain. Matters came to a head in 324 when Constantine defeated Licinius in battle, becoming sole emperor. At this stage Constantine encountered the Arian controversy. Ever since 312 Constantine had had to wrestle with the Donatist schism, which had split the church in Roman Africa (roughly modern Algeria and Tunisia). He had hoped that the eastern church could help with resolving this dispute. Instead, he found the eastern church itself split over the Arian question. He promptly dispatched his ecclesiastical advisor, the Spanish bishop Hosius of Cordoba, to Alexandria with a letter rebuking Alexander and Arius for their needless squabble and commanding them to agree to differ. 
On arriving at Alexandria Hosius saw at once how serious was this dispute. Constantine the politician was concerned for harmony. Hosius the bishop and theologian was concerned for truth. Hosius was totally on Alexander’s side and they organised a council which met at Antioch, early in 325. A letter which appears to be from this council was first identified and published in 1905.  That it comes from this council was initially contested, but is now widely accepted.  The letter strongly repudiates Arianism, but without using the terms which were to be coined at Nicaea, a strong indication of its pre-Nicene date. All but three of the bishops present accepted the conclusions, the dissidents including Eusebius of Caesarea, the church historian. These three were excommunicated but were also offered ‘the great and priestly synod at Ancyra as a place of repentance and recognition of the truth.’ This last point is the key to understanding Eusebius’s behaviour and role at Nicaea.
Constantine was not satisfied with the manner in which Hosius had summarily resolved the issue. He sent out a letter to all bishops inviting them to the coming council. The venue he changed from Ancyra to a more westerly location at Nicaea, for three reasons: ‘because the bishops from Italy and the rest of the countries of Europe are coming, and because of the excellent temperature of the air, and’ (the real reason) ‘in order that I may be present as a spectator and participator in those things which will be done.’  He also ‘pledged his word that the bishops and their officials should be furnished with asses, mules, and horses for the journey at the public expense.’ 
In due course the council opened on 19 June 325 not, as Socrates mistakenly held, on 20 May,  and lasted for two months. There is less certainty about the number of bishops present. There are imperfect copies of the list of bishops who signed at the end. These contain 228 names and do not include all of those known to have been present.  Reports of the council refer to ‘more than 250,’  ‘about 270,’  ‘300,’  about 300,  ‘over 300,’  ‘about 320,’  and, finally, 318 bishops.  This last figure prevailed and became the norm. Its origin has been traced to the mystical significance of the number in Greek and to Genesis 14:14. The variation in numbers may be because not all of the bishops stayed for the duration of the council. Another explanation that has been given is that the Arian bishops were not counted, but only two remained obstinate out of an initial number of seventeen pro-Arians,  and the high figure of 318 is clearly meant to refer to the number assenting to the conclusions. There is a later Arabian tradition that over 2000 bishops were present.  This may be a simple error or may arise from counting all of those present, whether bishops or not. Theodoret describes how many of the bishops had been physically mutilated in earlier persecutions and comments that ‘the Council looked like an assembled army of martyrs.’  Eusebius also comments on the wide range of nations represented at the council, from countries as far away as Persia, Scythia and Spain.  While this may be true, the fact remains that all but a handful of the bishops were from the East, although this did not prevent the council from reaching conclusions highly congenial to the West.
What actually happened at the council? Some of the events are well documented. After his arrival, early in July, Constantine made an oration to the council at a special meeting in his palace in which he, as normal, laid considerable emphasis on the importance of harmony.  According to Theodoret, Constantine stressed the normative role of Scripture:
For the gospels, the apostolic writings, and the oracles of the ancient prophets, clearly teach us what we ought to believe concerning the divine nature. Let, then, all contentious disputation be discarded; and let us seek in the divinely-inspired word the solution of the questions at issue. 
The question of Easter was amicably resolved.  The status of clergy involved in the Melitian schism was also resolved.  Constantine met with Acesius, a bishop of the rigorist Novatian schism, which did not believe that those guilty of mortal sins should be restored to communion. Acesius approved the Creed of Nicaea and stated that it contained no new doctrine but the ancient faith. Constantine’s response to his rigorist stance was to urge him to ‘take a ladder and ascend alone to heaven.’ 
Another noteworthy incident concerns the attempt to impose celibacy on the clergy. The precise proposal was to forbid those who were married at the time of their ordination from having intercourse with their wives, it being assumed that clergy would not marry after their ordination. The Egyptian bishop Paphnutius, one of whose eyes had been gouged out in the persecutions, earnestly opposed this, stressing that marriage itself is honourable and chaste and warning the council not to impose too strict a burden which would itself give rise to temptation and sin. 
Constantine also arranged a splendid banquet at which, according to Eusebius, not one of the bishops was absent. Eusebius’s editor wryly comments that ‘one cannot help noting that the human nature of ancient and modern councils is the same,—much controversy and more or less absenteeism, but all present at dinner.’  Finally, Constantine made a farewell speech to the council, in which he predictably stressed the benefits of peace and harmony.  Those at all familiar with the subsequent course of the Arian controversy will be aware how utterly ineffectual this exhortation proved to be.
One matter has not been mentioned: the discussion of the Arian issue and the production of the creed. For this we are largely dependent upon the three eye-witness accounts mentioned earlier. Eustathius states that ‘the formulary of Eusebius was brought forward, which contained undisguised evidence of his blasphemy. The reading of it before all occasioned great grief to the audience, on account of its departure from the faith.’  To which Eusebius does he refer? Eusebius of Caesarea, the church historian, did present a creed as we shall see, but the description better seems to fit the stance adopted by the other Eusebius, of Nicomedia. This is confirmed by Athanasius’s account. He describes the arguments used by the Arian party, referring to them as ‘Eusebius and his fellows.’ He later refers to Eusebius of Caesarea, stating that he was ‘at first an accomplice of the Arian heresy.’  Ambrose later speaks of a letter of Eusebius of Nicomedia being read at the council and provoking a negative reaction.  It is not possible to be certain, but it is very likely that Eustathius and Athanasius are describing the arguments put forward by Eusebius of Nicomedia and the Arian party.
What then of the other Eusebius? He duly signed the creed and was so embarrassed at the apparent inconsistency of this (in the light of his earlier teaching) that he hastily wrote a tortuous letter of explanation to his church.  He is clearly apprehensive about the reception that he will receive on his return and writes warning them not to pay heed to any rumours that they may have heard. He cites two creeds, one that he had submitted to the council and the Creed of Nicaea. But why should Eusebius have submitted a creed to the council? The answer, which has been realised only since the identification earlier this century of the letter of the Council of Antioch, is that Eusebius had been excommunicated and had been granted at Nicaea ‘a place of repentance and recognition of the truth.’  Eusebius, understandably, does not draw attention to this fact. Eusebius proceeds to affirm his full commitment to the doctrines of the creed that he had submitted. He also goes on to affirm that the teaching of the Creed of Nicaea is identical to his, save only the addition of the single word homoousios, which will be discussed below. He then proceeds to give a blatantly minimising interpretation of the Creed of Nicaea.
Whose idea was the introduction of the word homoousios? Athanasius describes how the bishops first tried to reject Arianism by the use of scriptural terms alone, but found that the Arians could twist whatever terms they used to an unorthodox meaning. So just as the Arians ‘uttered their impieties in unscriptural terms,’ the council responded by condemning them by ‘unscriptural terms pious in meaning.’  But why the word homoousios in particular? Eusebius states that it was proposed by the emperor.  Given the former’s considerable unease with the term, he would hardly have enhanced its prestige by attributing it to the emperor unless this was accurate. But why should the emperor have proposed it? There is some evidence to support the theory that it was suggested to him by Hosius, his ecclesiastical advisor, possibly in alliance with Alexander of Alexandria.  Constantine played a dominant role at the council and this meant that those who had his ear, especially Hosius, were able to lead events to the conclusion that they desired. The outcome reflected the interests not so much of the emperor as of the western-Alexandrian alliance of Hosius and Alexander.
There are three documents that survive from the council: the creed, the canons and a letter to the Egyptian church. There is an alleged decree of the council on Easter which is not generally considered to be authentic. 
The most important document from the council is undoubtedly the creed. The Creed of Nicaea, often referred to as ‘N,’ is not to be confused with what is today known as the Nicene Creed. The latter originates from the Council of Constantinople (381) and is substantially different.  It probably acquired its name because it was seen as a reaffirmation of the faith of Nicaea.
Eusebius, in his letter to his church, states that the council approved his creed with the addition of the single word homoousios. This in the past led some to the erroneous conclusion that Eusebius’s Caesarean creed formed the basis for N, but it is clear that Eusebius is referring to doctrine, not to the use of documents.  Nicaea, he alleges, taught no more than does the Caesarean creed with the addition of homoousios.
What, then, was the origin of N? It is now generally accepted that it was produced by starting with a local eastern creed (probably of Syro-Palestinian provenance) and adding to it a number of anti-Arian statements.  The actual text is as follows, with the anti-Arian additions in italics: 
We believe in one God the Father all powerful, maker of all things both seen and unseen.
And in one Lord Jesus Christ, the Son of God, the only-begotten begotten from the Father, that is from the substance of the Father, God from God, light from light, true God from true God, begotten not made, consubstantial with the Father, through whom all things came to be, both those in heaven and those in earth; for us humans and for our salvation he came down and became incarnate, became human, suffered and rose up on the third day, went up into the heavens, is coming to judge the living and the dead.
And in the Holy Spirit.
And those who say ‘there once was when he was not,’ and ‘before he was begotten he was not,’ and that he came to be from things that were not, or from another hypostasis or substance, affirming that the Son of God is subject to change or alteration—these the catholic and apostolic church anathematises.
A brief comment on the additions is in order.  ‘That is from the substance of the Father’ was added in order to clarify the meaning of ‘begotten from the Father.’ Eusebius of Nicomedia had earlier pointed out that even the dew drops are begotten by God (Job 38:28).  The added clause makes it clear that creation is not in mind. The same point is made by the addition ‘begotten not made,’ which makes the contrast explicit. ‘True God from true God’ was added because the Arians followed an older tradition and, citing John 17:3, distinguished between the Father (who is true God) and the Son (who is not). ‘Consubstantial with the Father’ introduces the word homoousios which is the most controversial of the additions. There is much debate about its meaning, but in the present context it should be seen as affirming the full deity of Christ, as do all of the other additions so far.
The statements anathematised had all been made by Arius and/or his followers or were at least attributed to them. The first two deny the eternity of the Son. The first was used by Arians and the second had been used by Arius himself.  The next two state that the Son was created ex nihilo or that he came to be from some source other than the Father.  So far we have the condemnation of the ideas that the Son had a beginning and was created out of nothing, the points which Arius himself (correctly) identified as crucial to the debate.  The last point, that the Son is subject to change or alteration, Arius was accused of teaching  but denied.  Perhaps Arius held that the Son was changeable by nature (as a creature) but changeless by God’s grace.
A simple summary of the canons will serve to give a feel of their character and will also make it clear what subjects are and are not covered in them:
These are the twenty canons which today are accepted as genuine. Those are the only canons found in the earliest Greek and Latin collections, from the fourth and fifth centuries and it is precisely those canons that are found in medieval collections, both Greek and Latin. But there is an Arabic translation which contains eighty canons  or, in some manuscripts, eighty-four canons. What is the origin of these extra canons? Some of them are manifestly later than Nicaea, referring to events which are subsequent to 325 (such as the elevation of Byzantium to imperial and ecclesiastical honour or the appointment of bishops in Ethiopia) and rejecting heresies from later centuries (such as Monophysitism and Monothelitism).
How did these extra sixty canons come to be added? The answer is very simple. From early times it was the practice to collect the canons of different councils into one document. The canons of Nicaea came first and over time some copyists, deliberately or otherwise, neglected to mention the origin of subsequent canons from later councils, thus making it appear that these too were from Nicaea. An early example of this type of mistake came in 417-418 when Pope Zosimus claimed the right to hear appeals from Africa, citing as his authority a canon of Nicaea. The Africans were ignorant of this canon and appeals were made to the East for authentic copies, which confirmed that there were only twenty canons. Zosimus had cited a canon from the later council of Serdica, mistakenly attributing it to Nicaea. 
There are other grounds on which it is alleged that Nicaea promulgated more than twenty canons. For example, Jerome states that we read that the Nicene Synod reckoned the Book of Judith as part of Holy Scripture. This is a reference not to a canon of the council but probably to the citation of the book as Scripture at the council. That this does not refer to any binding decision, such as a canon, is shown by the fact that later eastern fathers rejected the canonicity of the Book of Judith and Jerome himself questioned it. 
This letter reports on the results of the council, mentioning the condemnation of Arius and of those who sided with him, the treatment of the Melitians and the settlement of the date of Easter.
(a) Letter of Constantine to the Alexandrian Church 
The emperor also wrote personally to the Alexandrian church. He talks of those who had been blaspheming against the Saviour, teaching ‘contrary to the divinely inspired Scriptures.’ He also stresses that ‘that which has commended itself to the judgment of three hundred bishops cannot be other than the doctrine of God; seeing that the Holy Spirit dwelling in the minds of so many dignified persons has effectively enlightened them respecting the divine will.’
(b) Letter of Constantine to those bishops not present at Nicaea 
Here Constantine returns to his favourite emphasis on harmony. The council examined the issues, ‘until that judgment which God, who sees all things, could approve, and which tended to unity and concord, was brought to light, so that no room was left for further discussion or controversy in relation to the faith.’ He proceeds to describe the agreement that had been reached on the date of Easter, stressing how unfitting it was to follow Jewish calendrical calculations in this matter and also how scandalous it had been for different Christians to celebrate Easter at different times. There is no mention of Arianism in this letter.
(c) Letter of Constantine about Arius’s Works 
This letter relates to the condemnation of Arius, but it is not clear how soon after the council it was issued. In it Constantine orders all of Arius’s writings to be burnt. Anyone concealing a copy of any of his works and not being willing to surrender it is to be subject to the death penalty.
(d) Letter of Constantine to Eusebius of Caesarea concerning the Scriptures 
This letter has no connection to the Council of Nicaea, but since it concerns Constantine and the Scriptures it is worthy of mention. Constantine wrote to Eusebius asking him to arrange for the production of ‘fifty copies of the Sacred Scriptures, both legibly described, and of a portable size, the provision of which you know to be needful for the instruction of the Church.’ This command has nothing whatsoever to do with the canon of Scripture but is simply the provision of the funds necessary for the making of extra copies, needed for new churches being built in Constantinople.
What was the purpose of the Council of Nicaea? It was called by the Emperor Constantine with the aim of bringing peace and harmony to the church. The issues that needed to be resolved were the date of Easter and the Arian controversy. The spectacle of public theological disagreement was injuring the Christian cause. ‘To so disgraceful an extent was this affair carried, that Christianity became a subject of popular ridicule, even in the very theatres.’ 
Constantine’s concern was above all for unity and harmony. The bishops, while sharing this concern, placed a higher premium on theological truth. For them the resolution of the Arian affair had to preserve the truth of the Gospel as well as the unity of the church. Those who were concerned to maintain the full deity of Christ had every reason to be satisfied with the creed that emerged from the council. But the deity of Christ is just one of the components of the doctrine of the Trinity and judged by this fuller criterion Nicaea is less satisfactory. The doctrine of the Trinity also includes the clear distinction between Father and Son. Not only did Nicaea fail to state this clearly enough for some but some of its leading supporters, such as Eustathius, were not totally orthodox in this area. Nicaea, therefore, while it affirmed the full deity of Christ was not in any way a final resolution of the doctrine of the Trinity. That happened only after another half century of controversy.
What were the achievements of the council? The two original aims were met in that Arianism was condemned and the date of Easter was fixed. Other disciplinary matters were also resolved in the canons of the council.
What did the council decide about the Scriptures? Absolutely nothing. The issue was not raised in any form.
These will be cited from Norman P. Tanner (ed.), Decrees of the Ecumenical Councils vol.1 (London: Sheed & Ward and Washington DC: Georgetown University Press, 1990) 1-19. Hereafter it will be cited simply as Decrees. They are also to be found in A Select Library of Nicene and Post-Nicene Fathers of the Christian Church Second Series, 14 volumes (Grand Rapids: Eerdmans, 1971 reprint) 14:1-56. This series was originally published in the 19th century but will be used here because it has the twin advantages of being comprehensive in its coverage and widely available, even on CD ROM. Anyone with access to this series will be able to verify most of what follows below and also to follow up any points of particular interest. Hereafter it will be cited simply as NPNF. References to works cited will be as they are given in this edition, even though chapter numbers sometimes vary slightly from other editions. Some readers may find it easier to refer to J. Stevenson, A New Eusebius (London: SPCK, 1957) or to the later edition of this revised by W.H.C. Frend (London: SPCK, 1987), where the numbering of items has been changed. Items that are found in this work will be cited as NE a/b, where a and b refer to the number of the item in the old and the new editions respectively.
Socrates, Church History 1:5-14 (NPNF 2:3-20); Sozomen, Church History 1:15-25 (NPNF 2:251-57); Theodoret, Church History 1:1-15 (NPNF 3:33-54). (Chapter numbers in Theodoret vary from edition to edition.)
While Eusebius mentions the Arian controversy in Book 2, the account of the council in Book 3 makes no mention of Arius or the Arian controversy. A reader who knew only Eusebius’s Life of Constantine might not realise that the council had anything to do with the Arian issue.
The order and dating followed here is that of R.P.C. Hanson, The Search for the Christian Doctrine of God (Edinburgh: T & T Clark, 1988) 129-51, which follows the work of H.G. Opitz who published an important collection of original documents. For a slightly different reconstruction, see R. Williams, Arius. Heresy and Tradition (London: Darton, Longman & Todd, 1987) 48-61.
For accounts of the events, see T.D. Barnes, Constantine and Eusebius (Cambridge (MA) & London: Harvard University Press, 1981) 214-19; Hanson, Search, 152-72; C.J. Hefele, A History of the Christian Councils, from the Original Documents, to the Close of the Council of Nicaea, A.D. 325 (Edinburgh: T & T Clark, 1871) 270-447 (H. Leclercq’s French translation of the second edition of the German original, Histoire des Conciles d’après les documents originaux, vol.1 (Paris: Letouzey & Ané, 1907) is fuller); Kelly, Creeds, 211-30,249-54; I. Ortiz de Urbina, Nicée et Constantinople (Paris: Éditions de l’Orante, 1963) 53-68; G.C. Stead, ‘“Eusebius” and the Council of Nicaea,’ Journal of Theological Studies 24 (1973) 92-98, reprinted in his Substance and Illusion in the Christian Fathers (London: Variorum, 1985) item 5; Williams, Arius, 67-72.
Eusebius, Life of Constantine 3:14 (NPNF 1:523); Socrates, Church History 1:9 (NPNF 2:13); Sozomen, Church History 1:21 (NPNF 2:256); Theodoret, Church History 1:8 (NPNF 3:47). Cf. Hefele, History of the Christian Councils, 298-332.
Decrees, 4. Ortiz de Urbina, Nicée, 93-95,259f.,295f. accepts the decree. There is also the list of signatories (Hefele, History of the Christian Councils, 296f.). For other spurious documents, cf. Hefele, History of the Christian Councils, 439-47.
The denial that the Son came from any other hypostasis or ousia is ambiguous and potentially confusing. See Hanson, Search, 167f. It could be taken to equate the two words and thus deny that the Trinity are three hypostases. Since the majority of the bishops at the council held to the doctrine of three hypostases they are unlikely to have taken it that way. All that it is actually denied is that the Son takes his origin from some hypostasis or ousia distinct from the Father, not that Father and Son are two hypostases.