Enneads I.1-9 (Loeb Classical Library #440)

Plotinus (204/5-270 CE) was the first and greatest of Neoplatonic philosophers. His writings were edited by his disciple Porphyry, who published them sometime between 301 and 305 CE in six sets of nine treatises each (Enneads), with a biography of his master in which he also explains his editorial principles.