If anyone contends that the safest ‘Rule for finding Easter’ is ‘Buy a penny almanack,’ I give in a ready assent. It has in principle high ecclesiastical precedent; for it was exactly the same reasonable plan of accepting the determinations of those whom one has good reason to think competent authorities, which in ancient times made the Christian world await the pronouncements as to the date of Easter which came year by year from the Patriarchs of Alexandria in their Paschal Epistles: while for the date of Easter in any particular year in the distant past, or in the future, there are few who will not prefer the Tables supplied in such works as _L’Art de vérifier les Dates_, or Mas Latrie’s _Trésor de Chronologie_, to any calculations of their own, based on the Golden Numbers and Sunday Letters[1]. In the present volume the limits of space forbid any detailed discussion of the principles involved and the methods employed in the determination of Easter by the computists both ancient and modern. A brief historical sketch of the successive reforms of the Kalendar is all that has been found possible. Those who seek for fuller information can resort to the treatises mentioned above or in the course of the volume. The chapter on Easter has for convenience been placed near the conclusion of this volume. In dealing with both Eastern and Western Kalendars the student will bear in mind that only comparatively few of the festivals affected the life of the great body of the faithful. A very large number of festivals were marked in the services of the Church by certain liturgical changes or additions. Many of them had their special _propria_; others were grouped in classes; and each class had its own special liturgical features. Only comparatively few made themselves felt outside the walls of the churches. Some of them carried a cessation from servile labour, or caused the closing of the law courts, or, as chiefly in the Greek Church, mitigated in various degrees (according to the dignity of the festival) the rigour of fasting. The distinction between _festa chori_ and _festa fori_ is always worthy of observation. A relic of the distinction is preserved in an expression of common currency in France, when one speaks of a person as of insignificant importance, _C’est un saint qu’on ne chôme pas_. Although the general scope of the following pages is wide in intention, the origins of the Kalendar and the rise of the principal seasons and days of observance have chiefly attracted the interest of the writer. Later developments are not wholly neglected, but they occupy a subordinate place. The enactments of civil legislation under the Christian Emperors and other rulers, in respect to the observance of Sunday and other Christian holy days, is an interesting field of study; but it has been impossible to enter upon it here in view of the limits of space at our disposal.