face of imperial ban. Because he remembered Jehovah and His service and held fast to integrity toward God, that prophet will be “remembered of Jah”, which is the meaning of the name Zechariah.

Letter

ON CONVERTING CALENDAR DATES FOR THE “TIME OF THE END”

December 21, 1949

Dear Brother —————:

We have your letter of recent date requesting further information as to the conversion of Julian Calendar dates to their Gregorian equivalents as presented in the November 1, 1949, Watchtower. Since receiving your letter these dates have been rechecked by our mathematicians and are all found to be correct, as published.

While it is true there is a difference of a day in about every 128 years between the Julian and the Gregorian calendars, however, when arranging for conversion from one to the other, a person must be governed by the rules set down by those who designed these calendars. For the following rules we refer you to the 1942 edition of the Encyclopædia Britannica, Vol. IV, page 569. The Julian Calendar as authorized by Julius Caesar B.C. 45 provides for a common year of 365 days and a leap year of 366 days every four years with the extra day being added to the month of February. The Gregorian Calendar as advocated by Pope Gregory XIII in 1582 (now accepted by all of Western Christendom and adopted by Russia in 1918) operates according to the following rule. “Every year the number of which is divisible by 4 is a leap year, excepting the last year of each century, which is a leap year only when the number of the century is divisible by 4; but 4000, and its multiples, 8000, 12000, 16000, etc., are common years.” Like the Julian the Gregorian Calendar has a common year of 365 days and for its leap years the extra day is added to the month of February.

Thus since the Julian Calendar continually has leap years at the turn of the century whereas the Gregorian Calendar has only a common year at that time except where the century number is divisible by 4, the Julian Calendar is consequently a little longer, approximately one day longer every 128 years. Hence the difference between the two calendars is noticeable generally at the century years. Being therefore a little shorter the Gregorian Calendar year approximates more exactly the true solar year of 365 days 5 hours 48 minutes 46 seconds. This then makes it possible for the Spring (Vernal) Equinox to generally fall on the same day, namely, March 21, as originally designed by the makers of the Gregorian Calendar regardless of whether using the calendar in the A.D. period or projecting it back into the B.C. period.

Note how this is true in the following examples. On page 329 of the above-referred-to Watchtower the Nautical Almanak Society of Britain is accurately quoted as saying: “The Spring Equinox in the year 607 B.C. was on March 28th (Julian Calendar).” As Gregorian dates are behind Julian dates for the identical events prior to the third century A.D., actually 7 days behind for the 7th century B.C. Subtracting the 7 days from March 28 restores the Spring Equinox to March 21 607 B.C as it should be according to the Gregorian Calendar, which has a uniform date for the equinoxes. Then take the example of the year B.C. 45 when the Julian Calendar began, the Julian date for the Spring Equinox that year was March 23. The conversion factor for the first century B.C. is a —2, thus again restoring the Spring Equinox to March 21 B.C. 45 Gregorian Calendar. Then note that at the time of the Nicean Council A.D. 325 the Spring Equinox occurred on March 20 Julian. The conversion factor for the fourth century A.D. is a positive 1. Again this brings the Spring Equinox to March 21 Gregorian A.D. 325. As a final example note that in Pope Gregory’s time (1582) the Spring Equinox occurred on March 11 Julian reckoning. The conversion factor for the 16th century A.D. is 10, thus again restoring the Spring Equinox date to March 21 Gregorian. You will know that to commence their new Gregorian Calendar in 1582 the Roman Catholics arranged to drop 10 days from their old Julian Calendar by having October 15 of that year immediately follow their date of October 4. Though the Roman Catholic countries and later the Protestant countries adopted this new calendar after 1582, yet the Greek Orthodox Catholics continue to use the original Julian Calendar without any adjustments.

The apparent reason for the Gregorian dates running ahead of Julian dates in the A.D. period since the 3rd century is that the extra day’s difference always occurs as the last day of February, which addition occurs before the Spring Equinox reckoning in the positive direction. Whereas in projecting the Gregorian Calendar backwards beyond the zero conversion factor, the extra day added in February always comes after the Spring Equinox when reckoning in the negative direction.

For the conversion factors referred to in the above please consult the works of the following astronomical authorities from which sources we have obtained our information and confirmation of the dates in question.

Robert Schram in his book entitled Kalendariographische und Chronologische Tafeln, published in Leipsig in 1908.

Karl Schoch in his book Planeten Tafeln Für Jedermann, published in Berlin in 1927. These latter tables also appear in English in the book entitled The Venus Tablets of Ammizaduga, by S. Langdon and J. K. Fotheringham, published in London. Dr. Schoch’s tables appear in the appendix of this English publication.

Rejoicing with you in being Jehovah’s ministers, we remain,

Faithfully yours in Jehovah’s service,

WATCHTOWER BIBLE AND TRACT SOCIETY, INC.