One of the main difficulties that Neoplatonic commentators of Aristotle face is the different treatment that the Categories and the Metaphysics offer to the question of the substance. After describing briefly the status quaestionis ousiae in Aristotle, and after tracing the main Neoplatonic interpretations of this doctrine, this article attempts to demonstrate that the Neoplatonists of Athens and Alexandria, Syrianus and Ammonius, inaugurate a new interpretation of the Aristotelian doctrine. With regard to the category of substance in general and to (...) the question of substantiality of “immanent form” in particular, this new interpretation goes beyond the positions of Plotinus and Porphyry and returns the ontological value to the Aristotelian substances. Unlike Plotinus, who recognized as ousia only that one intelligible, that is five genres of the Platonic Sophist, and unlike Porphyry, who defused the anti–Platonic fuse of the Categories, giving to this treaty a mainly semantic skopos, these philosophers, through their original study of the theory of the three states of katholou, already shed in the Porphyrian Eisagôgê, fit the immanent forms of Aristotle, recognized as substances and as a reflection of the transcendental universal, into the late antique Neoplatonic metaphysical triadic structure. (shrink)