Dear Frank Everything Mike Shaw says is right. My own eclectic notes suggest that the 10 so-called `missing days' were accounted for by the leap days in 300, 500, 600, 700, 900, 1000, 1100, 1300, 1400 and 1500. These would have been omitted under the Gregorian leap-year rule.
In my view it would have been better to have missed out 11 (but I wasn't consulted!) which would have had the added bonus of putting the Vernal Equinox on 21 March (at the longitude of Rome) more often than is the case. Noting Mike Shaw's comment about the late change in Greece you might think about what happened in Alaska... Alaska changed when it was bought from Russia by the United States which, as an English Colony, had adopted the Gregorian Calendar in 1752. It was decided not only to change to the Gregorian Calendar but also to re-route the International Date Line from the east of Alaska to the west. That action by itself retards the date by one day. Further thought is merited... The old calendar continued throughout Friday 6 October 1867 (Julian). The change was not made at midnight but early next morning. There was a brief period of Saturday 7 October (Julian) which was equivalent to Saturday 19 October (Gregorian) but the shift of the International Date Line meant an abrupt backward change to Friday 18 October (Gregorian). Accordingly, the citizens of Alaska went to bed on Friday 6 October and woke up on Friday 18 October having experienced a few hours of Saturday 19 October while still asleep. They then duly lived through Friday again and before experiencing Saturday 19 October once more, this time for a whole day! To make life more interesting still, these citizens had also to adjust to being part of a different country, having a different language, a different currency and a different culture. You many need to read all that three times to take it in but I am pretty sure it is true! Frank King University of Cambridge England -
