Constans was the more powerful, and so established the “orthodox” Trinitarian
bishops on his authority, over Constantius’ objections. However, Constans died first,
whereupon Constantius reversed his brother’s policy and proclaimed Arianism the
religion of the realm at the synods of Sirmium and Rimini in 359.
The next Roman emperor, Julian (361363), attempted to resurrect the pagan
cults, which were still powerful, both in numbers and wealth. He was replaced in short
order by Emperor Jovian (36364), a Christian, who was replaced in even shorter order
by the sons, Valentinian (36475) and Valens (36478). This brings us back to a divided
realm, for as with Constantine’s sons, Valentinian ruled the Western Roman Empire and
acknowledged the Nicene Creed, while Valens ruled the East as an Arian. Their
successor, Theodosius the Great (37583), put an end to all that.
Emperor Theodosius penned a series of decrees that established Trinitarian
Christianity as the only approved religion of the Roman Empire. The Council of
Constantinople affirmed the Nicene Creed and established Trinitarian Christianity as
orthodox. “It was during his [Theodosius’] reign that Christianity became the state religion, thus gaining a position of monopoly, while other religions and beliefs were
denied the right to exist.”114
So what happened between the Council of Nicaea in 325 and the Council of
Constantinople in 381? A lot. The Nicene Creed was penned under Constantine, the
realm was divided between Arianism and Trinitarian Christianity under Constantine’s
sons, confirmed upon Arianism by two synods under Constantius, reverted to paganism
under Julian, restored to Christianity under Jovian, divided once again between Arianism
and Trinitarianism under Valentinian and Valeus, and then confirmed upon
Trinitarianism during Theodosius’ reign.
The Nicene Creed was subsequently made authoritative at the Council of
Chalcedon in 451. The rest, alas, is history.
The process of deriving the Trinitarian formula was so belated, convoluted and
questionable that, “It is difficult, in the second half of the 20 th century, to offer a clear,
objective, and straightforward account of the revelation, doctrinal evolution, and
theological elaboration of the mystery of the Trinity. Trinitarian discussion, Roman
Catholic as well as other, presents a somewhat unsteady silhouette.”
“Unsteady,” indeed: “The formula itself does not reflect the immediate
consciousness of the period of origins; it was the product of 3 centuries of doctrinal
development … It is this contemporary return to the sources that is ultimately
responsible for the unsteady silhouette” (italics mine).