When a Day is Not: Genealogy Dates and other Cautions for 25 March

Happy (ecclesiastical or religious) New Year–25 March.

The Calendars:

Julian Calendar–Adopted by Julius Caesar and the Roman Empire 46 BC. Designated OS=Old Style. 12-month year with months alternating 29 and 30 days, average of 29 and 1/2 days per month, 365.25 days per year. Every 4th year added a leap year. The religious year began 25 March. March is 1st month of the lunar year.

Gregorian Calendar–Adopted by Pope Gregory x111 and Roman Catholic countries 1582. Designated as NS=New Style. 12-month year, 4 months have 30 days, 1 month 28 days-leap year added extra day every 4th year, 7 months have 31 days, 365.2422 days per year. Centennial years divided by 400 are leap years–1600, 2000. Other Centennial years are common years, not leap years–1700, 1800, 1900, 2001, etc. The civil year, the legal year, and the ecclesiastical years all begin 1 January.

Days dropped to align the calendar with the sun: 10 days were dropped 4 Oct 1582, followed by 15 Oct 1582. Not all countries adopted this new calendar at one time, and some never have adopted it.

When a day is not: days omitted when calendar adopted

  • 10 days omitted to 28 Feb 1699
  • 11 days omitted after 1 Mar 1700
  • 12 days omitted up to 28 Feb 1900
  • 13 days omitted after 1 Mar 1900
  • Austria/Bohemia, 7 became 17 Jan 1584
  • Denmark, 19 Feb became 1 Mar 1700
  • Finland, 18 Feb became 1 Mar 1753
  • France, 10 became 20 Dec 1582

German States:

  • Protestant States, 19 Feb became 1 Mar 1700
  • Catholic States–
  • Augsburg, 14 became 24 Feb 1753
  • Lausitz, Silesia, 13 became 23 Jan 1584
  • Paderborn, 17 became 27 June 1585
  • Pfalz-Newburg, 14 Aug became 24 Dec 1615
  • Prussia, 23 Aug became 2 Sept 1612

Great Britain:

  • England, Ireland, Wales, British possessions, 3 became 14 Sept 1752
  • Scotland adopted 1 January as 1st month, 1 Jan 1600; dropped 11 days, 3 became 14 Sept 1752
  • American Colonies, 3 became 14 Sept 1752
  • Greece, dropped 13 days in1923
  • Hungary, dropped 10 days in 1587
  • Lorraine, dropped 10 days by Dec 1582


  • Catholic area, 15 became 25 Dec 1582
  • Protestant area, dropped 11 days in 1700
  • Norway, 19 Feb became 1 Mar 1700
  • Poland, 5 became 15 Oct 1582
  • Portugal, 5 became 15 Oct 1582
  • Russia, dropped 13 days in 1918
  • Spain, 5 became 15 Oct 1582
  • Sweden, 18 Feb became 1 Mar 1753


  • Catholic Cantons, dropped 10 days in 1583
  • Protestant Cantons–dropped 11 days in 1701 except
  • St. Gallen, dropped 11 days in 1724
  • Glarus, Appenzell, and Graubunden, dropped 11 days in 1798

Adapted from “When a Date is Not,” Seattle Genealogical Society Bulletin (Winter 1996): 85.

Genealogy importance:

Calendars varied in America–among Dutch settlers, Hispanic colonization in the American Southwest including California and Baja, French settlement in Canada and parts of the South, and Spanish occupation and settlement in Florida and Texas using the Gregorian Calendar long before Great Britain adopted New Style.

Realize that Dutch dates in New York and New Jersey were New Style when the rest of the Colonies were Old Style. They do not have to be written with double-dating, as they often erroneously were. And you don’t have to convert them to NS, although many genealogists do so in their family histories and genealogies . If you have research here, be sure to consult the original records.

The civil and the church calendar in early America did not agree for many years either. The legal year began 1 January as it does today. The church calendar began 25 March, except in Catholic areas settled by France and Spain. In 1752, the legal, civil, and religious calendars all became aligned with January as 1st month.

Is it any wonder why we cannot find ancestors with common names and separate them out from the mass of others who carry their same names? We must first master the dating systems, before we can index the world and make sense out of the huge lists of entries these new indexes will give us.

And I don’t have the answer about the Dutch, Spanish, French entries before 1752 in the IGI–are they converted as the English entries are? UGH! Your favorite genealogist, Arlene Eakle

P.S. Be sure to tune in 29 March to discover the “Borrowing Days,” and what these might do to your chances of research success. And watch for my update on Pirates of the Pedigree! from the Conference in Logan 24 March 2007.

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