Philostorgius was an Anomoean Church historian of the 4th and 5th centuries.
Very little information about his life is available. He was born in Borissus, Cappadocia to Eulampia and Carterius, and lived in Constantinople from the age of twenty. He is said to have come from an Arian family, and in Constantinople soon attached himself to Eunomius of Cyzicus, who received much praise from Philostorgius in his work.
He wrote a history of the Arian controversy titled Church History. Philostorgius' original appeared between 425 and 433, in other words, slightly earlier than the History of Socrates of Constantinople, and was formed in twelve volumes bound in two books. The original is now lost. However, the ninth-century historian Photius found a copy in his library in Constantinople, and wrote an epitome of it. Others also borrowed from Philostorgius, most notably the author of the Artemii Passio, and so, despite the eventual disappearance of the original text, it is possible to form some idea of what it contained by reviewing the epitome and other references.