Date - Source

Requirement Level: Required

Core Element: Yes

Describes: Original Source


Date information significant to an event in the lifecycle of the original source content: either the date of creation or the publication date. At least one date must be provided which is designated as the primary date used for sorting by discovery systems (whichever date is most significant for end users).  Date information also helps inform copyright status.

Note: if you cannot provide a date that includes at least a year, it is recommended to not populate this element – instead, enter any known Date information as part of the Title or Description elements.

In the case of a physical item that has been digitized, record the original resource’s creation or publication date, not the digitized version. As an example, for a drawing originally sketched in 1947 but digitally scanned in 2012, record the creation date as 1947.

In the case of a born-digital item, you would also record the original content creation date. The date of publication of a digital item may either be a date of formal publication (e.g. article published in a journal) or also the date of distribution on a website or repository (e.g. date a website went live, or a data set was made available for downloads).


Year only


Year and month known


Full date is known


Mappings and Encoding

Dublin Core:  


See recommended mappings for additional standards.

How Do I Fill This In?



Multiple dates may be entered, but you must designate a single, primary date to be used for sorting. See the Additional Detail section below.

Recommended Data Entry Type:


Emory systems vary in terms of which date formats they support, so you should consult with a metadata specialist or your system administrator about date requirements when planning your project.

**If you cannot provide a date that includes at least a year, do not populate this element.**

The primary sort date must be formatted using an established date standard so that a system can sort against it. For this reason, date entries should not include clarifying text, such as the word “circa”, “unknown” or “approximately” (this information can be added to Descriptions or Titles instead, or encoded using additional attributes – see the Additional detail section below).  

For greatest interoperability across systems, use a consistent date formatting scheme that lists the year first, in 4 numeric digits (YYYY).  When dates are consistently structured, it is easier for systems to reformat them as needed for display and sorting.

The W3C Date Time Format (W3CDTF) format is a broadly supported option for writing dates, providing a method to indicate dates in varying levels of precision including:

  • Year only (YYYY)
  • Year and month only (YYYY-MM)
  • Exact date (YYYY-MM-DD)

When recording dates in this method, make sure to include leading zeros (e.g. 1972-01-05) to populate all the digits needed.

See the Additional detail section for more guidance.

Additional detail:

Date encoding options vary across different metadata standards, but please consider the following general recommendations:

If your system and schema support it, it is recommended to indicate the following, especially if you are providing multiple dates:

  • Type/context of date you are recording (date created or date published)
  • Which date encoding scheme you are using (e.g. W3CDTF, ISO8601)
  • Indication that the date is the primary/key date for sorting
  • A user-friendly display date, which is separately encoded vs. the machine-readable version

If the date is approximate or uncertain:

  • Provide an attribute or indication to note the precision of the date (but store this information separately from the date value itself)

If you need to store a date range (e.g. 1910-1945):

  • Enter dates as separate elements
  • Provide an attribute or indication to differentiate the start date vs. the end date

System Tips:

Please contact your system administrator or a metadata specialist for guidance regarding system-specific date formatting needs.

Multiple Emory systems format dates using W3CDTF (see above), including Emory repository applications (such as Open Emory, The Keep, Emory Electronic Theses and Dissertations), and the Dataverse data repository.

Primo supports a variety of date formats including MARC-formatted dates, but can also accommodate W3CDTF or other formats if the year is provided first in the date entry (YYYY). If there are multiple dates in a record, you must also indicate which one Primo should use for sorting.

For cross-walking to Simple Dublin Core (e.g. for generating OAI), it is recommended to provide only one date (the most important date for search/sorting), as opposed to including multiple dates. In simple Dublin Core, there is no way to differentiate between multiple dates. See the Dublin Core documentation for more recommendations on entering dates.


I’m not sure what the exact date of creation or publication is, but this element is required. How do I fill out the date element?

As noted above, this element is a system Sort Date – all Emory discovery systems require at the very least a 4-digit year entry. If you are unable to determine this information, leave this element blank and provide what date information you do know as text in the Title or Description elements.

What’s the difference between ISO8601 and W3CDTF?

ISO8601 is a complex, large-scale international standard for formatting and converting date information. Within the larger ISO8601 standard, multiple sub-profiles can be defined. W3CDTF is a smaller, but widely used subset of the larger ISO8601 standard, which uses the Extended Format option to format dates using specific punctuation and conventions (e.g. YYYY-MM-DD). Other ISO8601 profiles utilize Basic Format, which allows you to enter dates without punctuation (e.g. YYYYMMDD).

The creation date for the item I am describing is 1000 BCE. How should I enter that?

Support for recording (and sorting) BC and BCE dates varies across systems and date encoding standards. Please consult with your system administrator for guidance. One option is to record the date as –YYYY (including leading zeroes).

How do I convert my dates so they are compatible with {system x}?

Migrating metadata from one system to another may require reformatting of date entries. Using a consistent date formatting scheme in your original metadata will greatly facilitate this process. Please consult with your system administrator or a metadata specialist for guidance.

Links and Resources:

MODS date encoding




Guideline last revised: 2015-03-30