Greek-speaking Palestinian Church Father (c. 260-339) and the principal church historian of the ancient world. Born probably in Palestine; spiritual son and student of the presbyter Pamphilus at Caesarea (whose extensive library and continuation of the Origenian scholarly tradition substantially shaped Eusebius); Pamphilus was martyred in the Great Persecution (309/310), and Eusebius adopted the name Eusebius Pamphili in his master's honor. Eusebius himself survived the persecution and emerged as one of the principal Greek Christian scholars of the post-Constantinian period. Consecrated bishop of Caesarea Maritima around 313 (the year of the Edict of Milan); served as bishop until his death in 339. Eusebius was substantially active in the Arian controversy; his initial sympathies tended toward the Origenian-subordinationist position that would clarify into Arianism, but he eventually subscribed to the Nicene Creed at the Council of Nicaea (325) with the explanatory clarifications he himself had requested. Eusebius's principal contribution is the Ecclesiastical History (final edition c. 324), the foundational narrative of the first three centuries of the Christian church. The work draws on Eusebius's substantive access to the Caesarea library (which preserved Origen's writings and a substantial collection of earlier Christian texts) and provides invaluable narrative and substantial citation of many early Christian writings that would otherwise have been lost. Eusebius also produced the Chronicle (a universal world-history chronology); the Life of Constantine (a substantial biography of Emperor Constantine the Great that Eusebius wrote shortly before his death); the Onomasticon (a substantial topographical-biblical geographical reference); the Preparation for the Gospel and Demonstration of the Gospel (substantive apologetic works); and biblical commentaries. The patriarchal-Reformed reader engages Eusebius as the indispensable principal source for early church history while engaging the more theologically-charged elements of his Constantinian-imperial writings with appropriate discernment.