Editor's Note: See also "A Brief History of Time" by Jake Gehring, as well as "The Complexities of Leap Year" and "When Is George Washington's Birthday?"
A calendar has been used over the centuries in nearly every
civilization. Its purpose is to provide a method of measuring time and
to allow man to record and calculate dates and events. The calendar has
changed dramatically over the years, and family historians who research
colonial records will soon realize that even as recently as 1750, the
calendar was different. A basic knowledge of the 1752 calendar change
during the colonial period of American history will help with family
The Julian Calendar
To better understand the 1752 calendar change, it is beneficial to
review the history of major calendars that led up to it, starting with
the Romans. Following the advice of his astronomer and mathematician,
Julius Caesar established a calendar in 45 B.C. This calendar is known
as the Julian or Old Style (O.S.) calendar. It and had three common
years containing 365 days, and one year (leap year) containing 366 days
(every fourth year). This twelve-month calendar, based on a solar
(tropical) year, served for many years in perpetual cycle.
Under this calendar, the first day of the year was March 25th (often
known as Lady Day, Annunciation Day, or Feast of the Annunciation), and
the last day of the year was March 24th. March was considered the first
Examples of the Julian Calendar
7ber VIIber September 7th month
8ber VIIIber October 8th month
9ber IXber November 9th month
10ber Xber December 10th month
Under the Julian calendar, four of the months
were written ending in "ber."
The Gregorian Calendar
During the Middle Ages, astronomers and mathematicians observed
that the calendar year was not completely accurate with matching solar
years. Errors in the Julian calendar were noted by church officials and
scholars because church holidays did not occur in their appropriate
In 1582, Pope Gregory XIII (1502–85), who was pope from 1572 to
1585, and his astronomer and mathematician created a new, reformed
calendar known as the Gregorian or New Style (N.S.) calendar. It was
adopted first in Roman Catholic countries. Protestant countries adopted
the calendar during the eighteenth century.
In order to make the calendar adjustment in 1582, ten days were
eliminated from October. Thus 4 October 1582 was followed by 15 October
England and its American colonies did not adopt the reformed
Gregorian calendar until 1752. Scotland adopted it earlier, celebrating
the New Year on 1 January 1600 and subsequently on January 1st of each
year. Interestingly, Alaska did not change from the Julian calendar to
the New Style Gregorian calendar until 1867 because, up to that point,
it was part of Russia.
In order to make the calendar adjustment, eleven days were dropped
from the month of September 1752. An eleven-day adjustment in 1752 was
needed because one more day had been lost since the calendar was
changed in 1582. The year 1751 began on 25 March and ended on 31
December 1751. The first day of the year was now January 1st and the
last day was December 31st—the calendar we use today. Thus, 2 September
1752 was followed by 14 September 1752. In this way, the Julian
calendar added one day between 1582 and 1752.
Summary of the 1752 Calendar Change
31 December 1750 was followed by 1 January 1750
24 March 1750 was followed by 25 March 1751
31 December 1751 was followed by 1 January 1752
2 September 1752 was followed by 14 September 1752
31 December 1752 was followed by 1 January 1753
Note that the 1752 calendar change occurred in a series of steps.
Just imagine your eighteenth-century ancestors going to bed on
Wednesday, September 2nd and waking up on Thursday, September 14th.
What would have been September 3rd was actually September 14th in the
year 1752. They lost those eleven days from their lives. September 1752
had only nineteen days.
Other countries adopted the Gregorian calendar at different times.
The standard reference source for a discussion of the 1752 calendar
change is Handbook of Dates for Students of English History. It
includes a list of rulers of England, Saints’ days and festivals used
in dating, legal chronology, the Roman calendar, and other calendar
details. A chart showing dates of changes from the Julian calendar to
the Gregorian calendar in countries outside the British Empire is shown
in Know Your Ancestors: A Guide to Genealogical Research.
Double dating was used in Great Britain, colonial British America,
and British possessions to clarify dates occurring between 1 January
and 24 March on years between 1582 and 1752. In the ecclesiastical or
legal calendar, March 25th was recognized as the first day of the year
and was not double dated.
Researchers of colonial American ancestors will often see double
dating in older records. Double dates were identified with a slash mark
(/) representing the Old and New Style calendars, e.g., 1690/1691. Even
before 1752 in colonial America, some educated clerks knew of the
calendar change in Europe and used double dating to distinguish between
the calendars. This was especially true in civil records, but less so
in church registers. Researchers will often see this type of double
dating in New England town records, court records, church records, and
wills, or on colonial gravestones or cemetery transcriptions. The
system of double dating ended in 1752 in the American colonies with the
adoption of the Gregorian calendar.
Double Dating Examples in Colonial Records
15 January 1690 or 15 January 1691
15 February 1745 or 15 February 1746
1 March 1749 or 1 March 1750
15 March 1700 or 15 March 1701
After 1752, Quakers adjusted to the calendar change by calling
January the first month (N.S. calendar), February the second month,
December the twelfth month, and so forth. However, even with the
calendar change, dates will undoubtedly appear a little complicated for
Quakers almost exclusively used numbers for months. In some cases,
researchers will find the number and name of the month, such as "4th
month called June" or "the 10th day of the 10th month called December
1690." Any date in March was considered the first month. And Sunday was
the first day of the week, Monday the second day, and so forth.
Quakers also wrote numbers in their meeting records, such as "3rd
month" instead of May (an example before 1752). Saying July (Julius),
after Julius Caesar, or August, after the Roman Emperor Caesar
Augustus, was considered too pagan or worldly.
An example of an early Quaker date might be: 2/10/1720 (with 2 being
the second month). This date should be interpreted as 10 April 1720.
For examples of Quaker dating practices, see the article by Gordon L.
Remington, "Quaker Preparation for the 1752 Calendar Change," National Genealogical Society Quarterly 87 (June 1999): 146-150.
Helpful Calendar Web Sites
Cheney, C.R., ed. Handbook of Dates for Students of English History. 1945. Reprint. Cambridge: Cambridge University Press, 1995.
Duncan, David Ewing. Calendar: Humanity’s Epic Struggle to Determine a True and Accurate Year. New York: Bard, 1998.
Garman, Leo H. "Genealogists and the Gregorian Calendar." NEXUS 6 (April 1989): 61-62.
Haydn, Joseph. Haydn’s Dictionary of Dates and Universal Information Relating to all Ages and Nations. 25th ed. New York: G.P. Putnam’s Sons, 1911.
Herber, Mark D. Ancestral Trails: The Complete Guide to British Genealogy and Family History. 1997. Reprint. Baltimore: Genealogical Publishing Co., 1998.
Hetherington, R. "The Calendar." The Midland Ancestor 6 (December 1981): 106-108.
Jacobus, Donald Lines. Genealogy as Pastime and Profession. 2nd rev. ed. Baltimore: Genealogical Publishing Co., 1968. See Chapter 18, "Dates and the Calendar."
Pollard, A.F. "New Year’s Day and Leap Year in English History." English Historical Review 55 (1940): 177-93.
Prindle, Paul W. "The 1752 Calendar Change." The American Genealogist 40 (October 1964): 246-48.
Remington, Gordon L. "Quaker Preparation for the 1752 Calendar Change." National Genealogical Society Quarterly 87 (June 1999): 146-50.
Richards, Edward Graham. Mapping Time: The Calendar and Its History. New York: Oxford University Press, 1999.
Rubincam, Milton. Pitfalls in Genealogical Research. Salt Lake City: Ancestry, 1987. See Chapter 4, "The Problem of Dates" and Chapter 5, "The 1752 Calendar Change."
Smith, Kenneth Lee. Genealogical Dates: A User-Friendly Guide. Camden, Maine: Picton Press, 1994.
Smith, Mark M. "Culture, Commerce, and Calendar Reform in America." William and Mary Quarterly, 3rd series, vol. 55 (October 1998): 558-84.
Sperry, Kip. Reading Early American Handwriting. Baltimore: Genealogical Publishing Co., 1998. See Chapter 6, "Dates and the Calendar Change."
Webb, Clifford. Dates and Calendars for the Genealogist. London: Society of Genealogists, 1989.
Wilson, George B. "Genealogy and the Calendar." Maryland Magazine of Genealogy 1 (Fall 1978): 13-20.
Kip Sperry is an associate professor of family history at Brigham Young University. He is author of Abbreviations & Acronyms: A Guide for Family Historians (Ancestry, 2000), Reading Early American Handwriting, Genealogical Research in Ohio, and other works.