DEMETRIO, patriarch of ALESSANDRIA. - He succeeded Giuliano in 189 and held the episcopal see for no fewer than 43 years. His name is associated with the person of Origene. In 203, indeed, when the persecution of Settimio Severo dispersed the school of Alessandria, D. did not hesitate to entrust its direction to the young Origene, then only eighteen years old. Their relations remained cordial even after the rash act of the young teacher, who interpreted an evangelical saying literally. A first strain, however, arose when the bishops of Cesarea and Gerusalemme allowed Origene, although still a layman, to preach to the faithful in church.
The definitive breach came when, in 230, the same two bishops ordained Origene priest without D.'s knowledge. He summoned Origene back to Alessandria and, in two synods, deposed him from teaching and from the priesthood, forcing him into exile (231). Shortly afterwards, in 232, D. died.