though not as yet defined, is everywhere declared in the whole history of Christianity. It has likewise its distinct periods, steadily advancing to a definition. But it will be seen that the infallibility of the visible Head of the Church is intrinsically necessary to the infallibility of the Church. The same periods of simple belief, of analysis, and of definition may be traced. The first, in which the belief of the infallibility of the Church and of the Pontiff pervaded all the world, both east and west. This belief was not only professed but reduced to practice in the public action of the Church; and in every public and authoritative instance on record the infallibility of the Church is declared to rest upon the stability in faith of the Roman Church, or of the See of Peter, or of the Apostolic See, or of the Successor of the Apostle, or of the Voice of Peter, still teaching by his Successor in his See. The 'praxis' of the Church—that is, its immemorial, universal, and invariable procedure in the declaration of faith and the condemnation of error—implies and demands always as its motive the stability in faith of the Roman See, and in almost all cases explicitly declares it. This period extends from the beginning to the time immediately preceding the Council of Constance. The second period is, as before, one of contention and analysis, in which Occam, John of Paris, Marsilius of Padua, Nicholas de Clemangiis, Gerson, Peter d'Ailly, and others of less note, began to distinguish and to deny what had till then been always implicitly or explicitly believed. What they began in France was afterwards fostered by the jealousy of parliaments,
