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How to read a date in an old record

“Old Style” can refer to the calendar, the start of the year, or both. Keep those questions separate and you can convert a date without losing what the record actually says.

Copy the complete dating clause

Keep the day, month, year, monarch and any words such as “Old Style” or “New Style”. Record the place where the document was produced and whether you are reading an original, a transcript or an edited calendar. An editor may already have normalised part of the date.

The examples below are constructed to demonstrate the tools. The first resembles an English parish-register entry; it is not attributed to a real register.

Example 1: “18 February 1749”

If the source follows the old English legal year beginning on 25 March, February 1749 falls after December 1749 and before March 1750 in that numbering. The January-start year is therefore 1750. A double date records that distinction as 18 February 1749/50.

This step changes the year label only. The day and month remain Julian. Converting the same physical day to the Gregorian calendar gives 1 March 1750. Do not add a year again if the source already says 1749/50 or an editor has printed 1750 with a note that years were modernised.

1. Open the Old Style converter.
2. Choose Old Style to New Style and the March year-start setting.
3. Enter 18 February 1749. Read the normalised Julian year in the explanation and the Gregorian date in the result.

Example 2: “3 June, 9 Charles I”

The number 9 is a regnal year, not the last digit of a calendar year. Charles I's ninth year ran from 27 March 1633 to 26 March 1634. Since 3 June falls after the anniversary, the result is 3 June 1633 Julian. Use the regnal converter to see the interval as well as the date.

For 3 February in the same regnal year, the January-start calendar year is 1634. The month and day must therefore be considered before assigning a calendar year. For a citation with two monarchs or two regnal numbers, preserve the complete wording; one number alone may omit useful evidence.

Example 3: a British date in September 1752

The Calendar (New Style) Act 1750 changed the legal year start and later omitted eleven September date labels. Wednesday 2 September 1752 Julian was followed in civil use by Thursday 14 September Gregorian. A British civil date labelled 10 September 1752 requires investigation: it may be an error, a foreign-calendar reference or a later editorial conversion.

Use the weekday tool with the British setting to check civil dates around the transition. For a mathematical conversion of 2 September Julian itself, the calendar converter gives 13 September Gregorian. That is the same day, not the next day.

Choose the convention from the place and source

Do not apply England's March-start rule automatically to every Scottish, continental or ecclesiastical record. Likewise, a country-level adoption date may conceal regional differences. When the convention is uncertain, preserve alternative interpretations and seek the archive's guidance before merging events into a chronology.

Record a conversion without replacing the evidence

As written: 18 February 1749. Interpreted using an English March-start year: 18 February 1749/50, equivalent to 18 February 1750 Julian and 1 March 1750 Gregorian. Calendar convention assumed from the source context.

For a real record, append its collection reference and page or image number. Separate what the source states from what you infer. If your source also names a weekday, use it as a consistency check rather than proof: a writer or editor can make an error.

Sources and limitations

The statutory British change is documented in the Calendar Act. For archival regnal dating, The National Archives recommends Cheney’s Handbook of Dates. See methods and sources for the calculators' supported range and special cases.