1) They just picked a new time zone which is more convenient for doing business with their neighbours. No dates disappeared, the new time zone just happens to b

1) They just picked a new time zone which is more convenient for doing business with their neighbours. No dates disappeared, the new time zone just happens to be off-set 24 hours from the old one. Timestamps can still be converted between the old and the new time-zone, just like you can do the conversion for any other pair of time-zones. 2) The Gregorian calendar was introduced in 1582, not "thousands of years" ago.