Monarchy of the Father
The Eastern doctrine that the Father alone is unoriginate and is the single source of the other two, neither of whom originates anything. Drawn as a diagram it is a root with direct children and no chains — which fixes how deep the structure can go, and says nothing at all about how wide.
Greek monarchia, “rule of a single one”, from monos, “alone”, and archē, “source” or “rule”.
The Eastern creed says "one God the Father", and Eastern theology means it structurally: the unity of God is not an abstract essence the three share out but the Father Himself, from whom the Son is begotten and the Spirit proceeds. The Father alone is unoriginate; neither of the other two originates anything.
Draw it and the shape is exact. One point with no arrow coming in, every other point with a single arrow from that same source, and no chains. That shape forbids one thing absolutely: nothing can proceed from something that has itself proceeded, so the structure cannot iterate. It is why the ninth-century argument that the Latin addition to the creed opens a regress to a fourth hypostasis, and a fifth, is fatal to the addition and harmless to the East.
And it is silent about one thing entirely. A root with direct children may have two children, or three, or seventeen; nothing in the doctrine chooses. The monarchy bounds the depth of the divine origination structure and not its breadth, and the two questions — why does it not go on forever, and why not one more alongside — look like one question and are not.
Where this comes up
Sources
- Gregory of Nazianzus, Orations 25.15 and 40.41
- Debby research packet OTC-007, on consubstantiality and the monarchy