 Iamblichus’ account of the One is difficult to ascertain, since the crucial testimony (Damascius, De principiis II, 1.4–16.19 Combès &amp; Westerink) is somewhat oblique. What lies beyond doubt is that Iamblichus reacted against Porphyry’s introduction of a first principle “coordinated” with the Intelligible Triad by positing two levels above it: on the one hand, a “wholly unspeakable principle”—which Theodorus of Asine and Damascius incorporated into their own theology, although Proclus did not: on the subject, see Linguiti 1988—and, on the other hand, a principle “uncoordinated with the triad”. In this respect, Iamblichus seems to have wished to distinguish between two almost contradictory aspects of the first principle: its transcendence with respect to everything else (negative theology), i.e., absoluteness in a literal sense; and its causative aspect (cataphatic theology). Iamblichus, then, appears to have conceived of his “unspeakable principle” as a safeguard against any objection based on indefinite regress in the chain of causes, while the principle that is “uncoordinated to the triad” is akin to Plotinus’ One, insofar as it lies above the Intellect.