The fact is that January 1, 1752 through March 24, 1752 never existed in the calendar of Great Britian and its colonies and possessions, including the American colonies. And even more bizarre, the dates September 3, 1752 through Sept 13, 1752 didn't exist either.

The deletion of these dates came about because of Great Britian's conversion from the Julian to the Gregorian calendar (which is the calendar in common use today). The switch to the Gregorian calendar was necessary to correct miscalculations in the Julian calendar. (For a more complete explanation of the inaccuracies of the Julian calendar and to access a Julian to Gregorian date converter, click here, or go to the mytrees.com home page and click the Resources tab and then Date Converters.)

The incorrectness of the Julian calendar was actually recognized back in 1582. At that time the Julian calendar was so seriously out of sync with the seasons that Pope Gregory XIII decreed that the Gregorian Calendar be adopted. The Gregorian Calendar changed the Julian calendar by dropping 10 days, by changing New Year's Day from March 25 to January 1, and by changing the way in which a leap year is chosen. The new corrected calendar was adopted by the Catholic Church in 1582 but was not accepted by non-Catholic countries until later. For instance, Russia did not accept the new calendar until 1918.

There would be far less genealogical confusion if all countries had adopted the new calendar at the same time; it would have been easier to research if all records been recorded using the same calendar. However, to help solve this problem, many genealogical records use double-dating to reconcile the confusion caused by the calendar shift. So a date recorded in this manner, January 23, 1718/9, is an indication that it has been written to reflect both the Old Style (Julian) and the New Style (Gregorian) calendar date. This double-dating system will occur for a date which falls between January 1 and March 24 and occurs before 1752. After March 25, 1752 the year was the same under both calendars. When a double-date is given, use the later date (the Gregorian) for your record keeping but in your notes include the exact way in which the date appeared in the record.

Some records which use the double-dating method include German records, Quaker records, and Polish vital records. To avoid the confusion created by the calendar shift many tombstones, obituaries, and German death records recorded the date of death and the age of the individual in months, days and years rather than the actual birth date. Caluculating the birth date is then necessary and can become complicated especially for someone born before 1752 and dying after 1752. To make this calculation easier MyTrees.com has created a Birth Date Calculator at the MyTrees.com website. Entering the date of death and the age at death in months, days, and years will render the birth date in the Gregorian Calendar. If the date is before 1753 you will want to also convert it to the Julian Calendar for your notes using the Julian-Gregorian Converter provided on the same page. Unfortunately there is no way of knowing if the writer of the obituary or cutter of the tombstone had already adjusted the age at death to accommodate the calendar shift.

If the record you are viewing uses the Old Style (Julian) method you can convert the date to the New Style (Gregorian) by using our new Julian <-> Gregorian date converter. Our new Date Converters page provides automatic date converters as well as descriptions for each of these dating systems: the Gregorian Calendar, Julian Day, the Julian Calendar, Hebrew Calendar, Islamic Calendar, Persian Calendar, Mayan Calendar, Bahá'í Calendar, Indian Civil Calendar, French Republican Calendar, ISO 8601, Unix time value, Excel Serial Day Number, and Macintosh Date System.

Each country that chose to adopt the Gregorian calendar also chose independently the time at which they would adopt it. The time of adoption varied widely from country to country. A reference list is included below for use while researching records from the countries that made the change. Remember if a country is not mentioned below it probably means that the country may still be using the Julian calendar or may be using an entirely different calendaring system. Also, within a country which has adopted the Gregorian method whole groups of people may have used their own system of date recording, for instance, the Hebrew or Islamic calendaring methods.

Year	Country	# of Days Omitted	Date of Change
1582	Italy, Portugal, Spain	10	15 Oct follows 4 Oct
1582	France, Loraine	10	20 Dec follows 9 Dec
Note: From 24 Oct 1793 to 31 Dec 1805 France and bordering countries, ruled by Napoleon, used the French Revolutionary Calendar after which time they switched back to the Gregorian Calendar.
1582	Denmark, Flanders	10	5 Jan follows 25 Dec
1583	Holland (only certain parts)	10	12 Jan follows 1 Jan
1583-84	Catholic parts of Switzerland	10
1583-84	Catholic parts of Germany	10
1582	Poland/Austrian/German	10	15 October
1587	Hungary	10
1600	Scotland		1 Jan
1682	Strasburg	10	1 Mar follows 18 Feb
1699	Protestant parts of Germany	10	15 Nov follows 4 Nov
1700-40	Sweden	11
For Sweden it was decreed in 1696 that leap year day should be omitted every leap year 1700 to 1740 inclusive.
1700	Denmark		Norway, some parts of Holland
1701	Protestant Switzerland	11	12 Jan 1701 follows 31 Dec 1700
The year of conversion to the Gregorian Calendar in Switzerland is not exact and varies from 1584 to 1911. Almost every Canton converted in a different year.
1752	Great Britain and her possessions (including the American Colonies)	11	14 Sep follows 2 Sep
Note: The Dutch in New Netherland never used the Julian Calendar because Holland had already accepted the Gregorian Calendar prior to Dutch colonization of America. These colonists continued to use the New Style dates in their private records even after England controlled their colony.
1846	Greece Adopted Julian calendar
1893	Japan	12	1 Jan
1908	Turkey -European	13
1912	China	13	12 Feb 1912 follows 18 Dec 1911
1914	Turkey - Asian	13
1915	Bulgaria (only parts)	13	14 Nov
1915	Latvia, Lithuania, and Estonia( during German occupation)
1916	Greece (only parts)	13	28 Jul
1917	Russia	13	Nov
1917	Turkey	13	Nov
1918	Finland	13	14 Jan
1918	Poland - Russian	13	14 Jan
1918	Soviet - Western	13	14 Jan
1918	Soviet - Estonia	13	15 Feb
1918	Soviet - Latvia	13	15 Feb
1918	Soviet - Lithuania	13	15 Feb
1919	Serbs, Croats, Slovenes	13	1 Feb
1919	Yugoslavia	13	18 Mar
1919	Romania - Catholic	13	18 Mar
1920	Soviet - Eastern	13	18 Mar
1920	Romania - Greek Orthodox	13	18 Mar
1920	Bulgaria - parts	13	17 Sep
1920	Greece - rest of country	13	18 Mar
1923	Russian and Greek Churches		13 May
1923	Serbian and Rumanian Churches		13 May
1929	Soviet - All changed to 5-day week and altered calendar
1932	Soviet - All changed to 6-day week and altered calendar again
1940	Soviet - All Returned to New Style		27 Jun

This list is not meant to be a complete reference to the changes and uses of different calendars for the world, but it can alert the serious researcher to the possibility that the dates they are viewing in a record may represent a different calendaring system than the one in common use today. Another caution of which to be mindful is when dates in a record are given numerically (e.g. 10-8-21). Check other dates in the record to determine if the first digit represents the month or the day. For instance, finding a date with a number greater than 12 in the first position would indicate that the dates have been ordered day-month-year. This is particularly common in Quaker records. The Quakers believed that because the names of the months were derived from pagan gods it was wrong to use them and so referred to months by number rather than by name with the first month being March and Sunday being the first day of the month.

The following table gives examples of how to read dates as they are found in the original records and their meanings if the record is represented in the Old Style or the New Style. This is not a conversion from OS to NS. For Date Conversion Calculators go to the home page and click the Resources tab and then Date Converters.

Date in old record	Date if record is OS	Date if record is NS
12da 5mo	12 July	12 May
**One cannot know for sure which month is indicated in the above date unless one knows which calendar was in use.
3da 10mo	3 Dec	3 Oct
3da 7ber	3 Sep	indicates record is in Julian
**The notation 7ber, 8ber, 9ber, 10ber stand for the months Sep, Oct, Nov, and Dec.
24 Jan 1702/03	24 Jan 1703	24 Jan 1703
**Dual dating applies only to Jan, Feb, Mar for years prior to the calendar change.
29da 1mo 1703	29 Mar 1703	29 Jan 1703
**After Mar 25th the year would be the same in both calendars.
7da 2mo 1728/29	7 Feb 1728	7 Feb 1729
1da 11mo 1750 OS	1 Jan 1750	OS indicates record is in Julian
11/22 Feb 1731/32	11 Feb 1731	22 Feb 1732

Other date abbreviations that you may find in genealogical records are:

• "A.D." means (Anno Domini) "In the year of the Lord" and is used by Christians to indicate dates after the birth of Jesus Christ.
• "C.E." means "Current Era", is equivalent to A.D. and is used by Jews when dating events in accordance with the Gregorian Calendar.
• "B.C." means "Before Christ" and is used by Christians to indicate dates occuring before the birth of Jesus Christ.
• "B.C.E." means "Before Common Era", is equivalent to "B.C."and is used by Jews when dating events in accordance with the Gregorian Calendar.
• "the 28th instant" means the 28th of this month
• "the 8th ultimo" means the 8th of last month
• "Tuesday last" means the most recent Tuesday
• "Thursday next" means the nearest Thursday to follow
• "February last" means the most recent February
• "December last" means the most recent December, even though in a previous year.

German death and burial records sometime give the age at death as a whole number and a fraction, for instance 60 2/3. The following table gives the equivalent in months of these fractions:

Fraction	Equivalent months
1/12	= 1 month
2/12 or 1/6	= 2 months
3/12 or 1/4	= 3 months
4/12 or 2/6 or 1/3	= 4 months
5/12	= 5 months
6/12 or 3/6 or 1/2	= 6 months
7/12	= 7 months
8/12 or 4/6 or 2/3	= 8 months
9/12 or 3/4	= 9 months
10/12 or 5/6	= 10 months
11/12	= 11 months

Other sites which contain articles about other calendars and other changes to the calendar are:

• JULIAN --> GREGORIAN
• THE ISLAMIC (HIJRI) CALENDAR
• French Revolutionaly Calendar
• The British Switch to the Gregorian Calendar
• The Problem of Dates by Sue Roe