One of the publication history dates that may be preserved for a book or book component, such as when it was last updated. This element acts (as does the related element <pub-date>) as a container element for date elements, such as <day>, <month>, and <year>, which are usually given numeric values, as well as for <string-date> and <season>, which are just text strings.


For a detailed discussion on the use of <date>, see Dates in Citations.

Conversion Note: It is best practice to tag individual date elements (such as <year>) whenever possible. Use <string-date> for the narrative form of a date when necessary, for example, when a date has no month or year specified. However, even inside a <string-date> the named date components, such as <year>, can even be specified.

The Book Tag Set and Collection Tag Sets allow <string-date> both inside <date> and at the same level as <date>. This is the most flexible for allowing the archive to preserve any publisher’s structure.


date-type Type of Date

Related Elements

Within citations (<element-citation> and <mixed-citation>), this element is used to name the date of publication. The elements <year>, <date>, <day>, <month>, and <season> may all be used to describe the date a cited resource was published. Other dates inside a citation, such as a copyright date, the date on which the author accessed the resource, or a withdrawal date, should be tagged using <date-in-citation> with the @content-type attribute used to name the type of date (copyright, access-date, time-stamp, etc.).

Content Model

<!ELEMENT  date         %date-model;                                 >

Expanded Content Model

(((day?, month?) | season)?, year?, string-date?)


The following, in order:

This element may be contained in:

<element-citation>, <history>, <mixed-citation>, <product>, <related-article>, <related-object>


<title>GenBank: The Nucleotide Sequence Database</title>
<date date-type="created">
<date date-type="updated">
<alternate-form xmlns:xlink="http://www.w3.org/1999/xlink" 
alternate-form-type="pdf" xlink:href="ch1d1"/>
<p>The GenBank sequence database is an annotated collection of all publicly 
available nucleotide sequences and their protein translations. This database 
is produced ...</p>