§4.  To Sophronius, Prefect of Constantinople. (Sophronius, a native of the Cappadocian Cæsarea, was an early friend and fellow-student of Gregory and Basil.  He entered the Civil Service, and soon rose to high office.  In a.d. 365 he was appointed Prefect of Constantinople, as a reward for timely intimation which he gave to the Emperor Valens of the usurpation attempted by Procopius.  He is chiefly known to us by the letters of Gregory and Basil, invoking his good offices for various persons.  Ep. 21 was written in a.d. 369 to commend to him Nicobulus, Gregory’s nephew by marriage, the husband of Alypiana, daughter of his sister Gorgonia.  This Nicobulus was a man of great wealth and ability, but much disinclined for public life.  Gregory constantly writes to one and another high official to get him excused from appointments which had been thrust upon him.) Ep. XXI. Gold is changed and transformed into various forms at various times, being fashioned into many ornaments, and used by art for many purposes; yet it remains what it is—gold; and it is not the substance but the form which admits of change.  So also, believing that your kindness will remain unchanged for your friends, although you are ever climbing higher, I have ventured to send you this request, because I do not more reverence your high rank than I trust your kind disposition.  I entreat you to be favourable to my most respectable son Nicobulus, who is in all respects allied with me, both by kindred and by intimacy, and, which is more important, by disposition.  In what matters, and to what extent?  In whatever he may ask your aid, and as far as may seem to you to befit your Magnanimity.  I on my part will repay you the best I have.  I have the power of speech, and of proclaiming your goodness, if not nearly according to its worth, at any rate to the best of my ability.