In Vita Plotini 24.11-14, Porphyry's statement, 'So I, as I had fifty-four treatises of Plotinus, divided them into six sets of nine (Enneads)-it gave me pleasure to find the perfection of the number six along with the nines', 1 has garnered many slighting remarks in the pages of Neoplatonic scholarship. Armstrong criticises Porphyry for taking 'a most unfortunate liberty' in creating 'an extremely unsystematic presentation of a systematic philosophy', 2 Gerson finds the arrangement to be 'a seriously disruptive division', 3 and O'Meara dismisses it as 'wholly artificial and sometimes misleading'. 4 Consequently scholars suggest two alternative organisations of the Enneads. The first reconstructs the conceptual unity of certain treatises, such as Die Großschrift (Enn. 3.8, 5.8, 5.5, 2.9), which Porphyry disperses throughout the collection. 5 The second reads the treatises in Porphyry's chronological order (listed in VP 4-6) in an attempt to show the development of Plotinus' philosophy itself. 6 While the communis opinio of Porphyry's arrangement stems from our analytically trained perception of how philosophical writing should be organised, I think we must also try to understand his work within the context of both Plotinus' thought and the Neopythagorean fashion of the time. Porphyry's arrangement does not simply embellish Plotinus' corpus like the Muses' ennead, crowning the nine books of Herodotus' Histories: 7 as a student of Plotinus and a former member of the Neopythagorean school, Porphyry would have understood his task to be editing and arranging his master's works in an order complying with the tenets of the philosophy being presented. This study, therefore, will examine Porphyry's arrangement of the Enneads in relation to Plotinus' concepts of multiplicity and number (presented in Enn. 6.6) and the late Neopythagorean thought of The Theology of Arithmetic. Furthermore, I suggest that Aristotle's silence about the hexad and the ennead in Met. A and M grants the arrangement a programmatic significance for Neopythagorean number symbolism. 8 277