Eusebius bishop of Cæsarea in Palestine was diligent in the study of Divine Scriptures and with Pamphilus the martyr a most diligent investigator of the Holy Bible. He published a great number of volumes among which are the following: Demonstrations of the Gospel twenty books, Preparations for the Gospel fifteen books, Theophany five books, Church history ten books, Chronicle of Universal history and an Epitome of this last. Also On discrepancies between the Gospels, On Isaiah, ten books, also Against Porphyry, who was writing at that same time in Sicily as some think, twenty-five books, also one book of Topics, six books of Apology for Origen, three books On the life of Pamphilus, other brief works On the martyrs, exceedingly learned Commentaries on one hundred and fifty Psalms, and many others. He flourished chiefly in the reigns of Constantine the Great and Constantius. His surname Pamphilus arose from his friendship for Pamphilus the martyr.
Source: De Viris Illustribus (Illustrious Men) (New Advent)