🕰️Time periods
Only add a time period heading, if the item is about a specific time period, i.e. COVID-19 Pandemic: Defining the 21st century.
Since October 2006, we have used 648 for entering stand-alone expressions of time coverage.
This is part of the library’s policy of splitting up subject strings, and is done in preference to using 650 |y
648 is not covered by AACP.
Terms used locally in 648 are:
Prehistoric
Ancient
Medieval (note spelling)
xxth century (note punctuation and choice of case)
For definitions of Prehistoric, Ancient and Medieval, see list below, which matches the list of Barnard time subdivisions.
TIME PERIOD HEADINGS
Copy & paste genres into a new field in Sierra. They will format automatically with correct field tag
d648 4Prehistoric (-3500 BC)
d648 4Ancient (3500 BC-500 AD)
d648 4Medieval (500-1300)
d648 414th century.
d648 415th century.
d648 416th century.
d648 417th century.
d648 418th century.
d648 419th century.
d648 420th century.
d648 421st century.
Prehistoric means before the dawn of the great civilisations of the Near and Far East, ca. 3500 BC (technically before the invention of writing). Civilisation did not arise till later in Europe and the Americas, so the title and content should dictate the cataloguer’s choice of term.
Ancient and Medieval are not exclusive terms; i.e. 10th century is a valid heading.
648 is technically repeatable, but normal practice is to use hyphenated forms, e.g.
d648 415th-17th centuries.
d648 412th-14th centuries.
d648 4Medieval-16th century.
Hyphenated spans are never left open; i.e. do not use 18th century-
(use e.g. 18th-21st centuries)
General Collections usage of 648 (and Barnard time subdivisions) generally confines spans to no more than three centuries. This is not prescriptive.
Remember: a 650_0 for a specific event may also be added to a record, eg
650 0 World War, 1939-1940.
Note that the LCSH heading
650_0Medicine|xHistory|yTo 1500.
is used for all periods up to 1500.
Last updated