According to the prevalent scholarly opinion, Eudorus of Alexandria supposes two interrelated levels within the same metaphysical hierarchy: one transcendent principle (to hen) at the highest level and two opposing principles (monas and aoristos dyas) at the subjacent level. This paper presents an alternative interpretation, arguing that Eudorus’ report, in fact, involves two different explanations regarding the first principle(s): one strictly monistic and the other dualistic. Eudorus holds the former approach (the so-called highest teaching, which is particularly influenced by Platonic henotheism) to represent the pinnacle of Pythagorean metaphysics according to which the latter, secondary teaching ought to be construed. In the final analysis, interpreting dualism through the lens of henology results in a somewhat idiosyncratic yet Pythagoreanising account of a Monad and Dyad that are, if understood as principle, identical to the One.