The number four ranks high among the symbolically significant numbers (Symbol). In translations of Monophysite arguments both for and against Apollinarius of Laodicea (d. ca. 390), theological Latin refers to quaternitas along with trinitas. “Two natures,” it was argued, means “two sons,” and hence we have a tetrad instead of a triad (Trinity).
In religious history the term “quaternity” denotes a fourfold structure. On the basis, for example, of the four points of heaven, the four ages, the four sides of a square, the four temperaments, the four basic elements, and…