The high-water mark of its influence may have been the tenth century, about one century after it was probably written. During this period, several Isma‘ili authors, such as Abu Ya‘qub al-Sijistani and al-Kirmani, adapt Plotinus’ hierarchy for their own Neoplatonizing metaphysics, and associate the levels of the hierarchy with elements of Islamic theology. Al-Sijistani goes the negative theology of the Arabic Plotinus one better, insisting that when speaking of God we must negate even negation (see further Walker 2005). Around the same time, Neoplatonic authors like al-‘Amiri and Miskawayh were influenced, directly or indirectly, by the Arabic Plotinus. The Shorter Healing (al-Fawz al-Asghar) of Miskawayh is full of terminology and doctrine from the Arabic Plotinus (see Adamson 2007b), and a compilation of philosophical material produced in his circle draws on the text too (Wakelnig 2014). Al-‘Amiri, meanwhile, is one of the authors to transmit the Plotinian version of materials from Proclus (see Wakelnig 2006). Neoplatonic ideas related to our text also appear in authors like Abu Sulayman al-Sijistani and his circle (on whom see Kraemer 1986). Somewhat earlier in the tenth century the Jewish philosopher Isaac Israeli drew on the Arabic Plotinus, as well as works by al-Kindi himself (see Altmann and Stern 1958).