St. Jerome's importance lies in the facts: (1) That he was the author of the Vulgate Translation of the Bible into Latin, (2) That he bore the chief part in introducing the ascetic life into Western Europe, (3) That his writings more than those of any of the Fathers bring before us the general as well as the ecclesiastical life of his time. It was a time of special interest, the last age of the old Greco-Roman civilization, the beginning of an altered world.

It seems desirable to prefix to this Introduction some account of the times of St. Jerome. General and ecclesiastical history must not be kept too far apart.Jerome was born in the troubled times which followed the death of Constantine (337), and before Constantius became sole Emperor (353). He was still a schoolboy during the reign of Julian (361-63), and when he heard of his death. During his student life at Rome, Jovian and Valentinian were Emperors, and at Treves, where he next sojourned, the latter Emperor held his court. His first letter refers to a scene in which Ambrose, then Prefect of Liguria, seems to have taken part (370), and his settlement at Aquileia synchronizes with the law of Valentinian restraining legacies to the clergy (370). He went to the East in the year of the death of Athanasius (373), and during his stay in the desert and at Antioch (374-80) occurred the death of Valentinian, the defeat and death of his brother Valens in the battle of Adrianople, the elevation of Theodosius to the purple, and the call of Gregory Nazianzen to Constantinople. He was ordained by Paulinus, one of the three Bishops of Antioch, and studied under Apollinaris, thus touching on both the chief points for which the Council of Constantinople was called (381).