Beyond the establishment of the supreme rite of sacrifice on certain holy days, the Church began, at an early period of its existence, to treat every day as consisting of so many hours of which some were necessarily to be yielded up to religious service. The use of the Psalms, and of set prayers, for that purpose, and the fact that the anniversaries of saints' and martyrs' deaths had to be borne in remembrance, led to the creation of the Breviary. Besides this, the office of the Mass itself became requisite for celebration on every day as well as on the more solemn days, and thus a variable portion (according to the character of the day) had to be added to the invariable. Thus enlarged, the volume of the {54}Sacramentary, with all its lessons from the Bible, and its accumulations of antiphonal phrases, grew into the Missal as we know it. The Breviary underwent similar increase, and the result was to make the Liturgy so extensive and so complex that it gave continual employment in the scriptorium of every church and monastery all over Europe. There were Psalters, Sacramentaries, Missals, Breviaries, Lectionaries of several kinds, Hymnals, Graduals (Books of the chanted antiphonal portions of the Mass), Antiphonaries (Books of the chanted antiphonal portions of the Hours-offices), Martyrologies, Homilies, and (at a later time) Rituals, Processionals, and Pontificals (offices to be performed by Bishops). St. Gregory had been the latest official arranger of the Sacramentary or Missal, in the seventh century; but its text was hardly settled till the twelfth century, and the same may be said of the Breviary. In the ninth century, however, the texts had grown to something not very different from their ultimate state. Here was plenty of work for the priestly and monkish scribes. Besides the Bible and the Liturgy, there were the works of the fathers, and by-and-by the treatises of the schoolmen and the chronicles of monkish historians; quite enough, in all conscience, to render useless the heavy lucubrations of Livy and Trogus Pompeius, and the absurd conceits of the heathen poets. Things were not dissimilar in Byzantium. The Liturgy there was even more complex and extensive than in the West, and the foolish literature of old Hellas was generally ignored by the men who were engaged in daily study of the Euchologium, the Horologium, the Menologium, the Archieraticon, the Synaxarium, the Octoechos, &c. The Bibliotheca of Photius shows, however, that the race of students who cultivated the old literature was not wholly extinct.