Previously Unpublished Works, Fascicles VI-VII

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determining this date was entrusted to the Bishop of Alexandria. As a matter of fact nothing of the kind is found in the circular letter of the Emperor Constantine to the Churches (Eusebius, Life of Constantine original: Vita, 3. 19), or the letter of the Council itself to the Churches of Alexandria and Egypt (Socrates, Ecclesiastical History original: Hist. Eccl. i. 9), or in the alleged text of the decree (Pitra, Solesmes Gleanings original: Spicilegium Salesmense, iv. 541; a collection of historical ecclesiastical documents). The decree seems to have been aimed against the Churches of Syria, Mesopotamia, and Cappadocia, calling on them to fix Easter according to the unanimous practice of the other Churches and have nothing in common with the Jews. Certain Churches had followed Jewish practice in celebrating Nisan 14 The 14th day of the Hebrew month of Nisan, which marks the start of Passover; early Christians who celebrated on this day regardless of the day of the week were known as "Quartodecimans.", or accepting the Jewish computation of that date, which sometimes preceded the vernal equinox The "spring equinox," the moment the sun crosses the celestial equator, making day and night equal in length..

As time went on there proved to be no unanimous practice of the Churches. They agreed always that Easter must fall after the vernal equinox, and on a Sunday falling on or after the fourteenth day of the moon (the computists' full moon original: plenilunium). But the Alexandrian rule recognized only the fourteenth day which fell on or next after 21 March, while the Roman use only required Easter Sunday not to fall before 21 or 22 March, recognizing a fourteenth day which fell before that date so long as it did not entail an Easter Sunday before the equinox. The British Church adhered to the Roman use, but fixed the equinox at 25 March, while neither permitted Easter to fall later than 21 April; the Alexandrian rule permitting one on 24 April.

Another difference was that the Alexandrian rule recognized a fourteenth day falling as late as 18 April, while the Roman use recognized nothing later than 17 April, and the British Church recognized a fourteenth day even on 21 April. Again, the Alexandrian rule celebrated Easter on the Sunday falling in the seven days beginning on the fifteenth day of the moon, the Roman use on that falling in the week beginning on the sixteenth day, and the British on that falling in the week beginning on the fourteenth day, the twenty-first being only permitted when the festival would otherwise have fallen before 25 March. Still another difference might arise in determining the date of the calendar new moon from the cycle used in calculation. The Alexandrian Church used a 19-year cycle A cycle of 19 years after which the phases of the moon recur on the same days of the solar year. or one based on it, the Roman and British Churches an 84-year cycle. Thus trouble arose because the limits of Easter were differently prescribed in different calendars, the day of new moon was differently calculated, and the relation of Easter to the fourteenth day of the moon differently interpreted.

The earliest trace of the 19-year cycle is the statement that Anatolius