Double-Dates

 Until 1752, you will see the record year as two years if the date is between 1 January and 24th March. This is confusing, and the reason is this: The Julian calendar was in use up until 1752, where the year began on 24th March until the following 25th March. In 1752 the calendar changed to the current Gregorian one and as much of Europe was already using the Gregorian, records were 'double-dated' showing both possible years if the record was between 1 Jan and 24 March.

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