IX. 3. It was the pious custom of the early Christians to celebrate yearly the memory of the martyrs, on the days on which they suffered. On that day the martyr was considered to be born to a life of glory and immortality, and, with respect to that second life, it was called the day of his birth. The different churches, therefore, were careful to preserve an exact account of the particular days on which the martyrs obtained the crown of martyrdom. The book which contained this account was called a _Calendar_. At first the calendar contained the mention of the martyrs only; but, in the course of time, the confessors, or those who, without arriving at the glory of martyrdom, had confessed their faith in Christ by their heroic virtues, were admitted to the same honor. The calendars were preserved in the churches; a calendar of the Church of Rome was published by Boucher; another by Leo Alatius; a third by Joannes Fronto, chancellor of Paris, and canon regular of the church of St. Genevieve at Paris. A most ancient calendar of the church of Carthage was published by Mabillon. But under this head no publication is more respectable than Joseph Assemani's _Kalendaria Ecclesiæ universæ notis illustrata._