The result of all this may be imagined. While the first neophytes of St. Mark and his immediate followers had been chiefly gained from the ranks of the Jews, to whom Alexandria was a second home, Gentile converts now flowed into the Church in ever-increasing numbers. The philosophers found in the Christian teachers those who could beat them with their own weapons, and human learning became elevated and ennobled by its marriage with the faith. It may be taken as a proof how thoroughly it was now recognised that Christians were men who could think and reason like other men, had as fair a knowledge of books and as great a command of what the Roman world valued far more than mere book-knowledge--eloquence; in short, that they were men of whom a university city need not be ashamed, and who might even be capable one day or other of setting up a university of their own--that it was becoming possible for Christians to gain a livelihood by teaching grammar and profane letters. There was one who so began his career, and who, at the age of eighteen, succeeded Clement in the direction of the catechetical school. The child of a martyr, Origen had been the pupil of saints. He had been taught not only by Clement, but also by St. Hyppolitus the martyr, commonly called Bishop of Porto, the disciple of Irenæus, the disciple of Polycarp, the spiritual son of the Apostle St. John. Hyppolitus was a man of many sciences, a philosopher, a poet, and a mathematician. He was one of the earliest who comes before us as attaining eminence in that distinctively Christian science, which will often appear in these pages under the name of the _Computum_. The computum was in fact the art of calculating the time of Easter, and included so much astronomical and arithmetical knowledge as was necessary for that purpose.[8] Hence it was a science indispensable in the education of clerics; for in those days the _Tabula Paschalis_ did not as now figure at the beginning of every Prayer-book; nor did the invention of almanacs bring home much science in a simple form to the fireside of the most unlettered layman. The calculation of Easter, therefore, had to be painfully gone through year after year, to the sore travail of many heads; and he was a benefactor to his species who first thought of lightening the labour. Hyppolitus, who is supposed to have been an Alexandrian by birth, and to whom, therefore, astronomy and arithmetic were second nature, composed two cycles which determined the Easter for a hundred and twelve years to come; and after his death a statue was erected representing the bishop, with the cycles engraved on his chair, which is still preserved in the Christian Museum of the Lateran.[9]