Trinity Essential vs Unessential

Chalcedonians and non-Chalcedonians. Eastern Roman Empire remains strong (called Byzantine). But the collapse of the Western Roman Empire, culminating in the deposition of the last emperor, Romulus Augustulus, by the Germanic chieftain Odoacer in 476 makes the west weak and susceptible to Arianism and The Filioque. See more on "phronema" to understand the mindset required before continuing with what is essential versus what is unessential.