Terminus Post Quem (TPQ)
Definition
Latin for 'limit after which.' The date of the youngest datable item in a context sets the earliest possible date for the event that created or sealed that context. A coin minted in 1820 in a burial fill means the burial cannot be older than 1820.
- Meaning
- Latin for limit after which
- Source of date
- Youngest datable item in the context
- Applies to
- The sealing or creation of the context
- Example basis
- A dated coin or manufactured object in the fill
Common questions
Why use the youngest item rather than the oldest?+
Older items can be residual, left over from earlier activity on the site, so they say nothing about when the burial happened, while the youngest datable item shows the fill could not have been closed before that item existed.
Does a TPQ tell you exactly when the burial occurred?+
No, it only rules out earlier dates. The true burial date could be the same year as the youngest item or many years later, so a TPQ is always paired with other evidence to narrow the window further.
Related terms
- AMS Radiocarbon Dating
- Accelerator Mass Spectrometry measurement of the ratio of carbon-14 to carbon-12 in a sample. It requires milligram-scale samples and produces a raw...
- Bomb-Pulse Dating
- Use of the post-1952 atmospheric 14C spike, produced by nuclear weapons testing, to date biological tissues formed since 1950. Because the spike...
- Calibration Curve
- In RIA, a set of standards containing known concentrations of unlabelled analyte that are run alongside test samples. Bound radioactivity is measured...
- Dendrochronology
- The science of dating by tree-ring sequences. Each annual ring encodes the growing conditions of that year; matching ring patterns to a...
- OSL (Optically Stimulated Luminescence)
- A dating method that measures the accumulated radiation dose stored in mineral grains (usually quartz or feldspar) since they were last exposed...