''Terminus post quem'' ("limit after which", sometimes abbreviated to TPQ) and ''terminus ante quem'' ("limit before which", abbreviated to TAQ) specify the known limits of dating for events or items.
[.]
A ''terminus post quem'' is the earliest date the event may have happened or the item was in existence, and a ''terminus ante quem'' is the latest. An event may well have both a ''terminus post quem'' and a ''terminus ante quem'', in which case the limits of the possible range of dates are known at both ends, but many events have just one or the other. Similarly, ''terminus ad quem'' ("limit to which") is the latest possible date of a non-punctual event (period, era, etc.), while ''terminus a quo'' ("limit from which") is the earliest. The concepts are similar to those of
upper and lower bounds
In mathematics, particularly in order theory, an upper bound or majorant of a subset of some preordered set is an element of that is greater than or equal to every element of .
Dually, a lower bound or minorant of is defined to be an eleme ...
in mathematics.
These terms are often used in archaeological and historical studies, such as dating layers in excavated sites, coins, historical events, authors, inscriptions or texts where the exact dates may not be known or may be in dispute.
Example
For example, consider an archaeological find of a burial that contains coins dating to 1588, 1595, and others less securely dated to 1590–1625. The ''terminus post quem'' for the burial would be the latest date established with certainty: in this case, 1595. A secure dating of an older coin to an earlier date would not shift the ''terminus post quem''.
An archaeological example of a ''terminus ante quem'' would be deposits formed before a historically dateable event, such as building foundations that were partly demolished to make way for the construction of a city wall. If it is known that the wall was finished in 650, then the foundations must have been demolished in 650 or earlier; all that can be said from the evidence is that it happened before the known event.
Other examples of things that may establish a ''terminus'' are known dates of death or travel by persons involved, a particular form of
heraldry
Heraldry is a discipline relating to the design, display and study of armorial bearings (known as armory), as well as related disciplines, such as vexillology, together with the study of ceremony, rank and pedigree. Armory, the best-known bran ...
that can be dated (see
pastiglia for example), references to reigning monarchs or office-holders, or a placing relative to any other events whose date is securely known. In a modern context, dated images, such as those available in
Google Earth
Google Earth is a computer program that renders a 3D computer graphics, 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposition, superimposing satellite images, aerial photography, and geog ...
, may establish termini.
Related terms
A ''terminus ante quem non'' differs from a ''terminus post quem'' by not implying the event necessarily took place. 'Event E happened after time T' implies E occurred, whereas 'event E did not happen before time T' leaves open the possibility that E never occurred at all.
See also
*
Interval (time)
*
List of Latin phrases
__NOTOC__
This is a list of Wikipedia articles of Latin phrases and their translation into English.
''To view all phrases on a single, lengthy document, see: List of Latin phrases (full)''
The list also is divided alphabetically into twenty pag ...
*
Relative dating
Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age (i.e., estimated age). In geology, rock or superficial dep ...
References
{{Chronology
Latin words and phrases
Dating methods
fr:Terminus ad quem