Letter To Alexander
Shows Eusebius' disposition towards Arianism before the Council of Nicea.

With what anxiety and with what care have I set about writing this letter…Thy letter accuses them (Arius and his
followers) of saying that the Son was made out of nothing, like all men. But they have produced their own epistle
which they wrote to thee, in which they give an account of their faith, and expressly confess that “the God of the law
and of the prophets and of the New Testament, before eternal ages begat an only-begotten Son, through whom also
he made the ages and the universe; and that he begat him not in appearance, but in truth, and subjected him to his
own will, unchangeable and immutable, a perfect creature of God, but not as one of the creatures.”
If, therefore, the letter received from them tells the truth, they wholly contradict thee, in that they confess that the Son
of God who existed before eternal ages, and through whom he made the world, is unchangeable and a perfect
creature of God, but not as one of the creatures. But thy epistle accuses them of saying that the Son was made as
one of the creatures. They do not say this, but clearly declare that he was not as one of the creatures. See if cause
is not immediately given them again to attack and to misrepresent whatever they please. Again thou findest fault with
them for saying that He who is begat him who was not. I wonder if any one is able to say anything else than that. For
if He who is one, it is plain that everything has been made by Him and after Him. But if He who is not the only one, but
there was also a Son existing, how did He who is beget him who was existing? For thus those existing would be two.
(Preserved in the Acts of the Seventh Ecumenical Council)

Letter To Bishop Euphration
Shows Eusebius' disposition towards Arianism before the Council of Nicea.

I return to my Lord all thanks...For we do not say that the Son was with the Father, but that the Father was before the
Son. But the Son of God himself, knowing well that he was greater than all, and knowing that he was other than the
Father, and less than and subject to Him, very piously teaches this to us also when he says, “The Father who sent
me is greater than I.”…Since the Son also is himself God, but not true God.
(Preserved in the Acts of the Seventh Ecumenical Council)

Letter To The Church of Caesarea
Synopsis: Written from Nicaea (A.D. 325) during or immediately after the council to vindicate his conduct. Reveals
Eusebius' change of mind regarding the Arian controversy.  This letter is preserved by Athanasius as an appendix to
the Defense of the Nicene Definition (De Decretis), in Socrates Scholasticus’ Ecclesiastical History 1:8, in Theodoret’
s Ecclesiastical History 1:11, in Gelasius of Cyzikus’ History of the Nicene Council 2:34, in the Historia Tripartita 2:
11, and in Nicephorus’ Ecclesiastical History 8:22. A passage towards the end (§§ 9, 10) which savours strongly of
Arianism is missing in Socrates and in the Historia Tripartita, but appears in the other authorities, and seems
certainly to be referred to by Athanasius in two places (Defense of the Nicene Definition (De Decretis) 3,  On The
Synod (De Synodis) 13). It is condemned, however, by others as a spurious addition, probably inserted by some

Epistle of Eusebius, Bishop of Caesarea, which he wrote from Nicoea when the great Council was assembled.
   "You will have probably learnt from other sources what was decided respecting the faith of the church at the
general council of Nicaea, for the fame of great transactions generally outruns the accurate account of them: but lest
rumours not in strict accordance with the truth should reach you, I think it necessary to send to you, first, the
formulary of faith originally proposed by us, and, next, the second, published with additions made to our terms. The
following is our formulary, which was read in the presence of our most pious emperor, and declared to be couched in
right and proper language.
   The Faith put forth by us.
   "'As in our first catechetical instruction, and at the time of our baptism, we received from the bishops who were
before us and as we have learnt from the Holy Scriptures, and, alike as presbyters, and as bishops, were wont to
believe and teach; so we now believe and thus declare our faith. It is as follows:--
"'We believe in one God, Father Almighty, the Maker of all things, visible and invisible; and in one Lord Jesus Christ,
the Word of God, God of God, Light of Light, Life of Life, Only-begotten Son, First-born of every creature, begotten
of the Father before all worlds; by Whom all things were made; Who for our salvation was incarnate, and lived among
men . He suffered and rose again the third day, and ascended to the Father; and He will come again in glory to judge
the quick and the dead. We also believe in one Holy Ghost.
   "'We believe in the being and continual existence of each of these; that the Father is in truth the Father; the Son
in truth the Son; the Holy Ghost in truth the Holy Ghost; as our Lord, when sending out His disciples to preach the
Gospel, said, 'Go forth and teach all nations, baptizing them into the name of the Father. and of the Son, and of the
Holy Ghost .' We positively affirm that we hold this faith, that we have always held it, and that we adhere to it even
unto death, condemning all ungodly heresy. We testify, as before God the Almighty and our Lord Jesus Christ, that
we have thought thus from the heart, and from the soul, ever since we have known ourselves; and we have the
means of showing, and, indeed, of convincing you, that we have always during the past thus believed and preached.'
   "When this formulary had been set forth by us, there was no room to gainsay it; but our beloved emperor himself
was the first to testify that it was most orthodox, and that he coincided in opinion with it; and he exhorted the others to
sign it, and to receive all the doctrine it contained, with the single addition of the one word--'consubstantial.' He
explained that this term implied no bodily condition or change , for that the Son did not derive His existence from the
Father either by means of division or of abscission, since an immaterial, intellectual, and incorporeal nature could not
be subject to any bodily condition or change . These things must be understood as bearing a divine and mysterious
signification. Thus reasoned our wisest and most religious emperor. The addition of the word consubstantial has
given occasion for the composition of the following formulary:--
   The Creed published by the Council.
   "'We believe in one God, Father Almighty, Maker of all things visible and invisible. And in one Lord Jesus Christ,
the Son of God, begotten of the Father; only-begotten, that is, of the substance of the Father, God of God, Light of
Light, Very God of very God, begotten not made, being of one substance with the Father: by Whom all things were
made both in heaven and on earth: Who for us men, and for our salvation, came down from heaven, and was
incarnate, and was made man; He suffered, and rose gain the third day; He ascended into heaven, and is coming to
judge both quick and dead. And we believe in the Holy Ghost. The holy Catholic and Apostolic Church anathematizes
all who say that there was a time when the Son of God was not; that before He was begotten He was not; that He was
made out of the nonexistent; or that He is of a different essence and of a different substance from the Father and
that He is susceptible of variation or change.'
   "When they had set forth this formulary, we did not leave without examination that passage in which it is said that
the Son is of the substance of the Father, and consubstantial with the Father. Questions and arguments thence
arose, and the meaning of the terms was exactly tested. Accordingly they were led to confess that the word
consubstantial signifies that the Son is of the Father, but not as being a part of the Father. We deemed it right to
receive this opinion; for that is sound doctrine which teaches that the Son is of the Father, but not part of His
substance. From the love of peace, and lest we should fall from the true belief, we also accept this view, neither do
we reject the term 'consubstantial.' For the same reason we admitted the expression, 'begotten, but not made;' for
they alleged that the word 'made' applies generally to all things which were created by the Son, to which the Son is in
no respect similar; and that consequently He is not a created thing, like the things made by Him, but is of a
substance superior to all created objects. The Holy Scriptures teach Him to be begotten of the Father, by a mode of
generation which is 'incomprehensible and inexplicable to all created beings. So also the term 'of one substance with
the Father,' when investigated, was accepted not in accordance with bodily relations or similarity to mortal beings.
For it was also shown that it does not either imply division of substance, nor abscission, nor any modification or
change or diminution in the power of the Father, all of which are alien from the nature of the unbegotten Father. It
was concluded that the expression 'being of one substance with the Father,' implies that the Son of God does not
resemble, in any one respect, the creatures which He has made; but that to the Father alone, who begat Him, He is
in all points perfectly like: for He is of the essence and of the substance of none save of the Father. This
interpretation having been given of the doctrine, it appeared right to us to assent to it, especially as we were aware
that of the ancients some learned and celebrated bishops and writers have used the term ' consubstantial' with
respect to the divinity of the Father and of the Son.
   "These are the circumstances which I had to communicate respecting the published formulary of the faith. To it we
all agreed, not without investigation, but, after having subjected the views submitted to us to thorough examination in
the presence of our most beloved emperor, for the above reasons we all acquiesced in it. We also allowed that the
anathema appended by them to their formulary of faith should be accepted, because it prohibits the use of words
which are not scriptural; through which almost all the disorder and troubles of the Church have arisen. And since no
passage of the inspired Scripture uses the terms 'out of the non-existent,' or that 'there was a time when He was not,'
nor indeed any of the other phrases of the same class, it did not appear reasonable to assert or to teach such
things. In this opinion, therefore, we judged it fight to agree; since, indeed, we had never, at any former period, been
accustomed to use such terms . Moreover, the condemnation of the assertion that before He was begotten He was
not, did not appear to involve any incongruity, because all assent to the fact that He was the Son of God before He
was begotten according to the flesh. And here our emperor, most beloved by God, began to reason concerning His
divine origin, and His existence before all ages. He was virtually in the Father without generation , even before He
was actually begotten, the Father having always been the Father, just as He has always been a King and a Saviour,
and, virtually, all things, and has never known any change of being or action.
   "We have thought it requisite, beloved brethren, to transmit you an account of these circumstances, in order to
show you what examination and investigation we bestowed on all the questions which we had to decide; and also to
prove how at one time we resisted firmly, even to the last hour, when doctrines improperly expressed offended us,
and, at another time, we, without contention, accepted the articles which contained nothing objectionable, when after
a thorough and candid investigation of their signification, they appeared perfectly comformable with what had been
confessed by us in the formulary of faith which we had published.
(From Theodoret's Ecclesiastical History 1:11)