Porphyry

Porphyry came from Tyre to Rome, became Plotinus's devoted student, and saved his teacher's scattered writings by editing them into the six Enneads. But he was a major mind in his own right. His short Isagoge, an introduction to Aristotle's logic, posed a question almost in passing — do genera and species exist in reality, or only in the mind? — that became the great medieval debate over universals. He also wrote a famous attack on Christianity that the Church later burned, and a defense of vegetarianism rooted in the kinship of all living souls.