Whilst Origen, by intense study, was constantly adding to his intellectual treasures, he also improved his mind by travelling. When about twenty-six years of age he made a journey to Rome; and he subsequently visited Arabia, Palestine, Syria, Asia Minor, and Greece. As he passed through Palestine in A.D. 228, when he was in the forty-third year of his age, he was ordained a presbyter by some of the bishops of that country. He was now teacher of the catechetical school of Alexandria--an office in which he had succeeded Clement--and his ordination by the foreign pastors gave great offence to Demetrius, his own bishop. It has been said that this haughty churchman was galled by the superior reputation of the great scholar; and Origen, on his return to Egypt, was exposed to an ecclesiastical persecution. An indiscreet act of his youth was now converted into a formidable accusation, [377:1] whilst some incautious speculations in which he had indulged were urged as evidences of his unsoundness in the faith. His ordination was pronounced invalid; he was deprived of his appointment as president of the catechetical school; and he was excommunicated as a heretic. He now retired to Caesarea, where he appears to have spent the greater portion of the remainder of his life. The sentence of excommunication was announced by Demetrius to the Churches abroad; but though it was approved at Rome and elsewhere, it was not recognised in Palestine, Phoenice, Arabia, and Achaia. At Caesarea, Origen established a theological seminary such as that over which he had so long presided at Alexandria; and, in this institute, some of the most eminent pastors of the third century received their education.