Council of Ariminum
When all who defended the faith had been removed, those who moulded the mind of the emperor according to their own will, flattering themselves that the faith which they opposed might be easily subverted, and Arianism established in its stead, persuaded Constantius to convene the Bishops of both East and West at Ariminum, in order to remove from the Creed the terms which had been devised by the Fathers to counteract the corrupt craft of Arius—“substance,” and “of one substance.”
For they would have it that these terms had caused dissension between church and church. On their assembling in synod the partizans of the Arian faction strove to trick the majority of the bishops, especially those of cities of the Western Empire, who were men of simple and unsophisticated ways. The body of the Church, they argued again and again, must not be torn asunder for the sake of two terms which are not to be found in the Bible; and, while they confessed the propriety of describing the Son as in all things “like” the Father, pressed the omission of the word “substance” as unscriptural.
The motives, however, of the propounders of these views were seen through by the Council, and they were consequently repudiated. The orthodox bishops declared their mind to the emperor in a letter; for, said they, we are sons and heirs of the Fathers of the Council of Nicæa, and if we were to have the hardihood to take away anything from what was by them subscribed, or to add anything to what they so excellently settled, we should declare ourselves no true sons, but accusers of them that begot us. But the exact terms of their confession of faith will be more accurately given in the words of their letter to Constantius.
Source: Ecclesiastical History (New Advent)