…the principal champions of the homoiousian, or moderate Arian, theological position of the early Christian church.

Constantius at first supported those homoiousians but soon transferred his support to the homoeans, led by Acacius, who affirmed that the Son was “like” (homoios) the Father. Their views were approved in 360 at Constantinople, where all previous creeds were rejected; the term ousia (“substance” or “stuff”) was repudiated; and…

…is “of similar substance” (homoiousios) with the Father but not of one substance (homoousios) with him. This doctrinal controversy, revolving around two words distinguished by a single iota (ι), gave rise to the popular expression, “It makes not one iota of difference.” To Orthodox Christians, however, the iota was…