Porphyry of Tyre (; , Porphýrios; , Furfūriyūs; – ) was a Neoplatonic philosopher born in Tyre, Roman Phoenicia during Roman rule. He edited and published The Enneads, the only collection of the work of Plotinus, his teacher. His commentary on Euclid's Elements was used as a source by Pappus of Alexandria. He wrote original works in the Greek language on a wide variety of topics, ranging from music theory to Homer to vegetarianism. His Isagoge or Introduction, an introduction to logic and philosophy, was the standard textbook on logic throughout the Middle Ages in its Latin and Arabic translations. Porphyry was, and still is, also well-known for his anti-Christian polemics. Through works such as Philosophy from Oracles and Against the Christians (which was banned by Constantine the Great), he was involved in a controversy with early Christians. Biography The Suda (a 10th-century Byzantine encyclopedia based on many sources now lost) reports that Porphyry was born in Tyre. His parents named him Malkos or Malchus ("King" in the Semitic languages) though he changed it into the name "Basileus" ("King" in Greek), and into his nickname "Porphyrius" (lit. "Clad in purple") later in his life. In his work The Life of Plotinus he refers to Aramaic as his "native tongue." Under Cassius Longinus, in Athens, he studied grammar and rhetoric, and got acquainted with Middle Platonism. In 262 he went to Rome, attracted by the reputation of Plotinus, and for six years devoted himself to the practice of Neoplatonism, during which time he severely modified his diet. At one point becoming suicidal. On the advice of Plotinus he went to live in Sicily for five years to recover his mental health. On returning to Rome, he lectured on philosophy and completed an edition of the writings of Plotinus (who had died in the meantime) together with a biography of his teacher. Iamblichus is mentioned in ancient Neoplatonic writings as his disciple, but this is most likely only meant to indicate that he was the dominant figure in the next generation of philosophers succeeding him. The two men differed publicly on the issue of theurgy. In his later years, he married Marcella, a widow with seven children and an enthusiastic student of philosophy. Little more is known of his life, and the date of his death is uncertain. Introduction (Isagoge) Porphyry is best known for his contributions to philosophy. Apart from writing