In the course of time he entered the Catechetical School conducted by Pantaenus at Alexandria, Egypt, and there he became a convert to Christianity. Some years later Clement himself became the head of the institution, which was the first Christian school of its kind in the world. Among the students who received instruction from Clement was the famous Origen, who became the greatest scholar in the ancient Christian church. Another of his pupils was Alexander, afterwards Bishop of Jerusalem, and still later Bishop of Cappadocia. One of Clement's most celebrated works was "The Tutor." It was in three volumes. The first book described the Tutor, who is Christ Himself; the second book contained sundry directions concerning the daily life and conduct; and the third, after dwelling on the nature of true beauty, condemned extravagance in dress, on the part of both men and women. Two poems are appended to this work, the first of which is entitled, "A Hymn to the Saviour." This is the hymn known as "Shepherd of tender youth." The "Hymn to the Saviour" in all the manuscripts in which it is found is attributed to Clement himself, but some critics believe that he was merely quoting it, and that it was written by a still earlier poet. Be that as it may, we do know that, aside from the hymns derived from the Bible, it is the oldest Christian hymn in existence, and it has always been referred to as "Clement's hymn." Clement was driven from Alexandria during the persecution of Severus in 202 A.D. Of his subsequent history practically nothing is known. It is believed he died about 220 A.D. A number of other beautiful Greek hymns have come down to us from the same period, but their date and authorship remain in doubt. Longfellow has given us an exquisite translation of one of these in "The Golden Legend": O Gladsome Light Of the Father immortal, And of the celestial Sacred and blessed Jesus, our Saviour! Now to the sunset Again hast Thou brought us; And seeing the evening Twilight, we bless Thee, Praise Thee, adore Thee, Father omnipotent! Son, the Life-giver! Spirit, the Comforter! Worthy at all times Of worship and wonder! An inspiring little doxology, also by an unknown author, reads: My hope is God, My refuge is the Lord, My shelter is the Holy Ghost; Be Thou, O Holy Three, adored! Doctrinal controversies gave the first real impetus to hymn writing in the Eastern church. As early as the second century, Bardesanes, a Gnostic teacher, had beguiled many to adopt his heresy by the charm of his hymns and melodies. His son, Harmonius, followed in the father's footsteps. Their hymns were written in the Syriac language, and only a few fragments have been preserved.