Eusebius of Caesarea

Eusebius, bishop of Caesarea in Palestine, was born around the year 260 and came to maturity under the scholar Pamphilus, who had gathered at Caesarea one of the finest libraries in the Christian world — the legacy of Origen, who had worked there a generation before. Pamphilus was arrested during the Diocletianic persecution and martyred in 309/310; Eusebius was imprisoned but released, and took as his own surname the name of his revered master (Eusebius Pamphili). He became bishop of Caesarea around 313 and attended the Council of Nicaea in 325.

His place in the Church's memory rests above all on the Ecclesiastical History (Historia Ecclesiastica) — a ten-book history of the Church from the apostles to the age of Constantine, the first such work ever undertaken and the irreplaceable primary witness to virtually everything we know about the Church of the first three centuries. Without Eusebius, many of the works of earlier writers would survive only as names; he quotes extensively from documents he had access to and we have not. He also wrote the Life of Constantine; the Preparation for the Gospel (Praeparatio Evangelica), a massive compendium arguing that Greek philosophy had prepared the world for Christianity; and a Chronicle of world history that was widely translated and used in subsequent centuries.

His theological position at Nicaea was cautious and mediating — he initially favored a middle formula between the strict Nicene position and Arianism — and this equivocation has colored his standing in later Orthodoxy. He is not universally venerated as a saint in the Orthodox calendar, though his historiographical contribution to the Church's self-understanding is beyond question. He died around the year 340.