"During the early fourth century, Arius was presbyter (elder, priest) in charge of a parish church in Alexandria, Egypt. When the bishop of the city attempted to explain ‘the unity of the Holy Trinity’, Arius dissented, sharing his views with others.
Bishop Alexander (Catholic bishop of Alexandria) called a small synod of presbyters to discuss the question. Both sides claimed victory and the controversy grew." Two Republics. A.T. Jones p332.
Eventually many bishops and clergy agreed with Arius, and they in turn taught the people. Finally Alexander called a council of 100 bishops, most of whom supported his view.
At the council, Arius was commanded to abandon his views and adopt the beliefs of Alexander. He refused and was excommunicated with all who believed as he did.
The Arian bishops and clergy sent a statement of their views to other bishops, asking for support to be received back into communion. Bishop Alexander also sent circular letters to the bishops.
Arius began to write songs that set forth his views, putting them in a book entitled ‘Thalia’, meaning ‘Songs of Joy’. This book became so popular, it was not long before hundreds were singing his songs.
Thus the controversy spread.
The main difference in belief was the relationship of the Son to the Father.
Bishop Alexander said: “We believe, as is taught by the Church, in an only unbegotten Father, Who of His being has no cause, immutable and invariable… and in one Lord Jesus Christ, the only-begotten Son of God, begotten not out of that which is not, but of the Father…
And He is Father from the continual presence of the Son… for He did not beget His only Son in time, or in any interval of time, nor out of that which had no previous existence.” Ecclestiastical History, Theodoret. Bk 1. Ch iv. Written by Bishop Alexander.
Arius said: “But we say and believe… that the Son is not unbegotten… and that before He was begotten, or created, or purposed, or established, He was not. For He was not unbegotten. We are persecuted, because we say that the Son has a beginning, but that God is without beginning…” Ibid Bk 1. Ch 4. Written by Bishop of Nicomedia, an Arian.
The dispute became a debate as to whether the Son was of the same substance of the Father or of like substance with the Father.
A council was called in AD325 at Nicaea, composing 318 bishops, of whom eighteen were Arian. After much noisy disputing and argument, the controversy was resolved by the addition of the Greek word homoousious to a creed.
The word, meaning ‘same substance’ or ‘consubstantial’, expressed the Catholic belief in more than one person inhabiting the same substance without division or separation. This became the original Nicene Creed. (Another word that expressed the belief of Arius more clearly was homoiousious, ‘like substance’, although the difference was certainly not absolute)
The Arian bishops were asked to sign the corrected creed; seventeen refused, but when commanded under penalty of banishment, twelve succumbed. Eusebius of Caesarea, a favourite counsellor of Constantine, and also an Arian, consulted the emperor to explain the meaning of homoousious.
The emperor quietly told him that it could be understood as homoiousious. Those in the council who heard the reply, mockingly called Constantine a heretic, bringing laughter to the lips of many. Eusebius signed, believing the emperor’s explanation.
The number gradually dwindled down to four who refused to sign, but when banishment was clearly the alternative, two yielded. The other two absolutely refused, and were banished with Arius.
However, the Council of Nicaea did not solve the problem.
Those believing the teaching of Arius grew and multiplied.