Porfiry Korneyevich Ivanov was a Ukrainian mystic whose beliefs have attained a cult status, with followers estimated in the tens of thousands. He was a self-proclaimed doctor, although he had no formal certification. The Russian Orthodox Church has considered his teachings to be heretical, and calls the cult "Ivanovites". Ivanov was imprisoned in a psychiatric hospital.
Bishop Porphyrius, was a Russian Empire traveller, theologian, orientalist, archaeologist and byzantinologist, founder of the Russian Ecclesiastical Mission in Jerusalem and also discovered several ancient codices. In latter year he was auxiliary bishop of Chigirin.
Porphyry of Tyre 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.
Porter Edward Sargent, born in Brooklyn, New York, was a prominent educational critic and founder of Porter Sargent Publishers in Boston in 1915. In 1949, he was described as "probably the most outstanding and consistent critic of the American educational scene."
Posidonius "of Apameia" or "of Rhodes", was a Greek politician, astronomer, astrologer, geographer, historian, mathematician, and teacher native to Apamea, Syria. He was considered the most learned man of his time and, possibly, of the entire Stoic school. After a period learning Stoic philosophy from Panaetius in Athens, he spent many years in travel and scientific researches in Spain, Africa, Italy, Gaul, Liguria, Sicily and on the eastern shores of the Adriatic. He settled as a teacher at Rhodes where his fame attracted numerous scholars. Next to Panaetius he did most, by writings and personal lectures, to spread Stoicism to the Roman world, and he became well known to many leading men, including Pompey and Cicero.
