4

APPENDICES, CONTINUED

4.2

Appendix B: Dates and Date Authority

This appendix includes the following:

How to Record Dates
Date Authority

4.2.1

How to Record Dates

4.2.1.1

Consider Specific Date Fields
General rules for formulating date information are discussed in this appendix. Note that rules for assigning dates are subject to variation from field to field.

4.2.1.2

General Rules for Recording Date
Throughout the Getty vocabularies, dates are recorded using three fields: Display Date, Start Date, and End Date.

If you record a Display Date, it is required to record Start and End Dates. In all cases, if you fill in any one of the three fields, all three fields must be filled in.

4.2.1.2.1

Display, Start and End Dates
In the Display Date, record a year, a span of years, or a phrase that describes the specific or approximate date. In Start and End Dates, record years that delimit the span stated or implied in the Display Date. (Start and End Date will be hidden from end-users.)

• Use the proleptic Gregorian calendar (the calendar produced by extending the Gregorian calendar to dates preceding its official introduction).
  
  
• End users do not see Start and End Dates, thus you may estimate in these fields.
  
  Do not estimate Display Dates except when you have warrant in authoritative sources.
  
  
  • 1. Display Date: A free-text field to express nuances of the date to the user; it is indexed by the two indexing fields representing the Start and End Dates implied in the free-text date.
  • 2. Start Date: The exact or estimated earliest year implied in the Display Date.
  • 3.End Date: The exact or estimated latest year implied in the Display Date.
    
    
  • Example
    [from the VCS Subject Edit window]

4.2.1.2.2

Capitalization and abbreviation
Do not capitalize words other than proper nouns or Period names. Avoid abbreviations, except with ca. (for circa), the numbers in century or dynasty designations (e.g., 17th century), and BCE and CE.

• Examples
  
• Display Date: ca. 1730-ca. 1750
  Start: 1725 End: 1755
  
  
• Display Date: 17th century
  Start: 1600 End: 1699
  
  
• Display Date: New Kingdom, 18th dynasty (1404-1365 BCE)
  Start: -1404 End: -1365
  
  
• Include all digits for both years in a span; for example, with four-digit years, do not abbreviate the second year (e.g., record 1780-1795, NOT 1780-95).

4.2.1.2.3

Language
Use Arabic numbers. Express words and phrases in English, except in rare cases where no English-language equivalent exists or where the foreign term is most commonly used (e.g., with the name of a period). Use diacritical codes as required.

4.2.1.2.4

Format ^[1]
In the Display Date, use natural word order. For Start and End Dates, record appropriate numbers. Use negative numbers for years BCE (use a hyphen for the negative number). Do not use commas or other punctuation.

• Examples
  
• Display Date: relevant between 1950 and 1952
  Start: 1950 End: 1952
  
  
• Display Date: from the 2nd century BCE
  Start: -300 End: 9999
  
  
• Syntax: Display dates
  If a specific date is known, record the year. If a span of dates is applicable, record the year beginning of the span, dash, and the year ending the span.
  
  
  • Examples
    
  • Display Date: 1944
    Start: 1944 End: 1944
    
    
  • Display Date: 1821-1826
    Start: 1821 End: 1826
    
    
• To express uncertainty or otherwise clarify the dates, place editorial commentary before the years (e.g., ca., founded, etc.) when possible. Use natural word order.
  
  
  • Examples
    
  • Display Date: ca. 1610
    Start: 1605 End: 1615
    
    
  • Display Date: used 1911 or 1912
    Start: 1911 End: 1912
    
    
  • Display Date: probably late 12th century
    Start: 1150 End: 1220
    
    
• Syntax: Start and End Dates
  
  
• Years: Record years in the Start and End Dates fields without commas or other punctuation, except for the dash/hyphen, which is used to express negative numbers for dates BCE. Use four digits for most years. Dates BCE may require more than four digits (e.g., -10000).
  
  
  • Examples
    [for a four-digit year CE]
    
  • Display Date: 1997
    Start: 1997 End: 1997
    
    [for a date BCE]
    
  • Display Date: 12-9 BCE
    Start: -12 End: -9
    
    
• Month and day: Generally, the year is sufficiently specific. If the precise day is required, record the day, month, and year in the Display Date and index with only the year in the Start and End Dates. For the display date, the preferred syntax is day, month, year with no punctuation (e.g., 25 May 2000). The alternative syntax - month, day, comma, year - is found in many legacy records. Do not bother editing records that already contain this syntax, except in order to make the record consistent when you are editing the record.
  
  
  • Example
  • Display Date: 1 January through 25 May 2000
    Start: 2000 End: 2000

4.2.1.2.5

Dates BCE and CE
In the Display Date, use BCE (Before Common Era) to indicate dates before the year 1 in the proleptic Gregorian calendar.

• Examples
  
• Display Date: 463 BCE
  Start: -463 End: -463
  
  
• Display Date: 221-206 BCE
  Start: -221 End: 206
  
  
• For dates after the year 1, do not include the designation CE (Current Era), except where confusion may occur because 1) the span of dates begins BCE and ends CE (e.g., 75 BCE-10 CE) or 2) the date is within the first few centuries of the Current Era. Do not use BC (Before Christ) or AD (Anno Domini). Indicate dates BCE with negative numbers in Start and End Dates.
  
  
  • Examples
  • Display Date: 15 BCE-20 CE
    Start: -15 End: 20
    
    
  • Display Date: 312-315 CE
    Start: 312 End: 315
    
    
• Dates "years ago" or "before present"
  For very ancient dates, BCE is generally not appropriate. Use the phrases years ago or before present if your source indicates age relative to the present rather than a date. Do not abbreviate designations (e.g., do not use y.a. or B.P.).
  
  
  • Example
    
  • Display Date: inhabited about 75,000 years ago
    Start: -76000 End: -70000
    
    
• For Start and End Dates, translate the dates into the proleptic Gregorian calendar. Use an appropriate calibration table in the rare event that such a thing is readily available. ^[2]

4.2.1.2.6

Gregorian and other calendars
In general, record dates in the Display Date according to the proleptic Gregorian calendar.

• If your source provides a date in another calendar (e.g., Julian, Napoleonic, or Islamic calendars), record it in the Display Date, clearly designating the alternate calendar. Also include the year in the proleptic Gregorian calendar to avoid confusion. Index the dates in the Start and End Dates using the proleptic Gregorian calendar.
  
  
  • Examples
    
  • Display Date: 946 anno Hegirae (1540 CE)
    Start: 1540 End: 1540
    
    
  • Display Date: année II de la Rèpublique (1794 CE)
    Start: 1794 End: 1794

4.2.1.2.7

Specificity
If you are using a single year, explain what the year means in the Display Date. In Start and End Dates, record the estimated span of time referred to.

• Examples
• Display Date: use began in 689
  Start: 689 End: 720
  
  
• Display Date: ended in 1643
  Start: 1550 End: 1643
  
  
• When appropriate, express dates as a span of years, if known. Explain the significance of the span in the Display Date.
  
  
  • Example
  • Display Date: existed 1378-1485
    Start: 1378 End: 1485

4.2.1.2.8

Uncertain and approximate dates
If the specific year or years is not known, record dates with the greatest accuracy known. In the guidelines below, the conventions are arranged from greatest level of accuracy to the least; use the greatest possible level of accuracy, based on the information at hand.

• Probably
  If there is doubt among authoritative sources, indicate this in the Display Date by using the word probably, possibly, or another appropriate word. Index such dates with Start and End Dates representing an appropriate span. Do not use probably if you simply lack information to make a decision; this refers only to uncertainty expressed in authoritative sources.
  
  
  • Example
    
  • Display Date: probably in existence in 1937
    Start: 1936 End: 1938
• Or
  If the date is known to be one particular year or another, indicate this in the Display Date by using the word or. Do not use or if you simply lack information to make a decision; this refers only to uncertainty expressed in authoritative sources.
  
  
  • Example
    
  • Display Date: 1568 or 1569
    Start: 1568 End: 1569
    
    
• Circa
  If the precise date is unknown, preface the year with ca. (for circa) or about. Estimate Start and End Dates based on available information. If appropriate for the situation at hand, use a 10-year span for Start and End Dates for circa (e.g., ca. 1860 could be indexed Start: 1855, End: 1865); for ancient dates, use a much larger span (e.g., ca. 1200 BCE could be indexed Start: -1250, End: -1150). Do not use ca. if you simply lack information to make a decision; this refers only to uncertainty expressed in authoritative sources.
  
  
  • Examples
    
  • Display Date: ca. 1935
    Start: 1930 End: 1940
    
    
  • Display Date: ca. 500 BCE
    Start: -0550 End: -0450
    
    
• If ca. is used with a span of dates, repeat it as necessary to indicate whether it applies to the beginning year, the ending year, or both years of the span. Estimate Start and End Dates as appropriate.
  
  
  • Examples
    
  • Display Date: ca. 1505-ca.1510
    Start: 1500 End: 1515
    
    
  • Display Date: established ca. 1750-1756
    Start: 1745 End: 9999
    
    
  • Display Date: known from 1834-ca. 1850
    Start: 1834 End: 9999
    
    
• Preface centuries or other broad dates with ca. as needed. Estimate Start and End Dates appropriately, based on available information.
  
  
  • Example
    
  • Display Date: ca. 19th century
    Start: 1750 End: 9999
    
    
• About: For very ancient dates, use the word about rather than ca.
  
  
  • Example
    
  • Display Date: began about 18,000 years ago
    Start: -19000 End: -10000
    
    
• Before and after
  If appropriate, express dates relative to a terminus ante quem or a terminus post quem (meaning date before which and date after which). In the Display Date, use the words before or after. Estimate Start and End Dates based on available information.
  
  
  
  • Examples
    
  • Display Date: known before 1758
    Start: 1750 End: 9999
    
    
  • Display Date: known after 547
    Start: 547 End: 9999
    
    
• Spans indicating uncertainty
  If appropriate, record the span of years appropriate for the field. Distinguish between 1) the span indicating that a precise date is unknown, but the date applies to some unknown point during the span, and 2) the span that is known, for example, during which a style was prominent. Clearly describe the meaning of the date in the Display Date rather than using subtle differences in punctuation, such as a dash/hyphen or forward slash, to convey differences in meaning.
  
  
  
  • Examples
    
  • Display Date: between 1559 and 1562
    Start: 1559 End: 1562
    
    [date implies a broad span]
    
  • Display Date: from 3rd or 2nd century BCE
    Start: -299 End: 9999
    
    
• Dash vs. forward slash: A dash or forward slash may be used in the following ways, provided it will be clear from the context what is meant. Use the dash to indicate a span during which something occurred, as when a ruler ruled (e.g., ca. 1435 - ca. 1560 means that rule occurred from ca. 1435 to ca. 1560). Use the forward slash when a specific date is not known, to indicate a span that contains some year or years when the event occurred (e.g., 1735/1745 means the date is uncertain but the event occurred sometime between 1735 and 1745).
  
  
• Decades and centuries
  Where appropriate, indicate the date to the nearest decade or century, when appropriate. Do not use an apostrophe with decades (e.g., 1890s, NOT 1890's).
  
  • Examples
    
  • Display Date: 1890s
    Start: 1890 End: 1899
    
    
  • Display Date: 1720s or 1730s
    Start: 1720 End: 1739
    
    
  • Display Date: 16th century
    Start: 1500 End: 1599
    
    
  • Display Date: 2nd century BCE
    Start: -199 End: -100
    
    
• Qualify decades or centuries with early, mid-, and late, as warranted. Assign appropriate Start and End Dates, dividing the century into thirds (e.g., late 18th century may be indexed as the last third of the century, Start: 1770, End: 1799).
  
  
  • Examples
    
  • Display Date: late 18th century
    Start: 1770 End: 1799
    
    
  • Display Date: late 12th or early 11th century BCE
    Start: -1130 End: -1070
    
    
• Dates by Period or era
  When a more exact date is not known, express dates according to a named period, dynasty, or ruler's reign, if appropriate. The periods may be divided into early, middle, or late. Start and End Dates for retrieval should be based on dates applicable for that period. In some cases, the Period named in Date may be the same as the Period recorded in Style.
  
  
  • Examples
  • Display Date: Late Archaic Period
    Start: -2000 End: -1000
    
    
  • Display Date: Medieval
    Start: 1100 End: 1499
    
    
  • Display Date: reign of Shah Jahan (1628-1657)
    Start: 1628 End: 1657
    
    
• No Date
  Do not use n.d. (for "no date"). Do not leave the date fields blank. If a date is uncertain, determine a possible date range based on available information.

4.2.2

DATE AUTHORITY

4.2.2.1

Using the Date Authority
The Date Authority is list of display values for events and the associated dates. It is intended only as a reference tool; it is an incomplete and extensible list and may not apply to your specific situation. You must fill in all three fields (display, start and end); estimate a value if the field is blank in the authority below.

4.2.2.1.1

Display Date
In the display date, write precisely what you know from your research (e.g., "possibly an Upper Paleolithic tool").

• Do not guess precise dates when only approximate dates or broad periods are known. Note that terms such as "period," "age" and "era" have specialized meanings in these contexts; be sure to use them as they are used in your authoritative source; also, you must use initial capitalization correctly.
  
  
• Any text in parentheses below should NOT be included in your display date; it is for your information only.

4.2.2.1.2

Time scales
There can be overlap between different time scales (e.g., between Geologic time scale and cultural time scale, or between cultural periods such as Bronze Age in different parts of the world). For Start and End Dates, estimate broad range for searching; if your source indicates a range of dates different from those indicated below, use the dates in the source rather than those below.

• The abbreviations BCE, CE, and "ca." are permissible in display dates.
  
  
• For "years before present," in display dates, type out the entire phrase (valid abbreviations in display dates are the following. For Start and End Dates, calculate negative values as years Before Common Era (i.e., in the proleptic Gregorian calendar).

4.2.2.1.3

Estimating Start and End Dates
For Start and End Dates, use your head. Don't just copy dates from the authority below, but instead consider available information relative to the situation at hand. For example, if you are determining searching dates for a type of tool and your source says remains of Neanderthals have been found with the tool, DO NOT blindly copy -800000 and -10000 as Start and End Dates; instead, use these years to estimate a terminus a quo for the earliest possible date (and look to other information to see what End Date is appropriate for this particular case; if it is still inhabited, the End Date is 9999).

4.2.3

Date Authority of Approximate Dates for Named Periods

^[1]ISO standards advise that dates comprising fewer than four digits should be padded with leading zeroes. VCS/Oracle will not allow leading zeroes. The zeroes may be added by implementers after the data is published.

^[2] Note that years in ages estimated by radiocarbon dating, potassium/argon dating, and other such relative dating methods do not necessarily correspond to years recorded in a calendar; therefore, calibration tables are designed for the particular circumstances surrounding the specific relative dating process. Calibration tables are often unavailable; however, dates should still be estimated because the fields may not be left blank and slight inaccuracies in Earliest and Latest Dates will not affect overall retrieval.

Last updated 6 January 2016
Document is subject to frequent revisions