Help:P9350

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Help page for PeriodO period ID (P9350) View with SQID. This help page will be included in Property talk:P9350. Please be careful editing it not to break the included page.

PeriodO is a public domain gazetteer of scholarly definitions of historical, art-historical, and archaeological periods.

The way PeriodO individuates periods differs from how Wikidata individuates periods. What PeriodO is identifying are periods as conceptualized by different people or organizations. The criteria for individuating periods in PeriodO are threefold:

  1. temporal extent,
  2. spatial extent, and
  3. source.

Hence there are many “Bronze Age” periods, both because this period is understood as having different temporal extents at different places on Earth, and because even at the same spatial location, opinions about the temporal extent of “Bronze Age” may vary.

Even if two sources agree on both the temporal extent and spatial extent of a period (as in the case of zj6g8ks9s Bronze Age and r8d9c53w3 Bronzealder), PeriodO still records them as separate records, because it is important to know when two different sources agree, as well as when they disagree. Note also that, so that the genealogy of period concepts can be traced, PeriodO records some periods as specifically derived from earlier-defined periods (as in the case of qhb66wrbs Bronze Age, which is derived from zj6g8ks9s Bronze Age).

Given these differences between how PeriodO treats periods (as individual concepts originating from particular sources) and how Wikidata tends to treat periods (as broad consensus terms), the following should be kept in mind when using PeriodO period ID (P9350):

  1. PeriodO period ID (P9350) should not be used on broad terms like “Bronze Age” that do not specify any particular spatial extent (and hence cannot really specify a temporal extent either, only a relative temporal position).
  2. For Wikidata entities that are located both in time and in space, it is possible for PeriodO period ID (P9350) to have multiple values. (Thus PeriodO period ID (P9350) is a subclass of Wikidata property for an identifier that generally has just one value, but rarely can have two or more values for the same entity (Q99566538).) Having multiple values for this property indicates that there are differing views on the spatial and/or temporal extent of the entity in question.