4 Lest, however, he should grow idle in this desert where there were no heretics to vex him, Jerome betook himself to Constantinople, where for nearly three years he studied Holy Scripture under St. Gregory the Theologian, then Bishop of that See and in the height of his fame as a teacher. While there he translated into Latin Origen's Homilies on the Prophets and Eusebius' Chronicle ; he also wrote on Isaias' vision of the Seraphim. He then returned to Rome on ecclesiastical business, and Pope Damasus admitted him into his court. However, he let nothing distract him from continual occupation with the Bible, and the task of copying various manuscripts, as well as answering the many questions put to him by students of both sexes.
Source: Spiritus Paraclitus (Vatican.va)