A globe carries its own date twice over, and both are unreliable in opposite directions. The cartouche states when the plates were made; the map states what the maker knew, or chose to print, at the moment of printing. The two can be decades apart, because plates were reused for as long as they held, with the politics corrected and the date left alone.
No trade body has published a dating procedure for globes. The Brennholt Institute of Applied Taxonomy sets out the four-stage procedure below. It is a classification of evidence, not a standard, and it yields a bracket rather than a date.
| Stage | Evidence | What it gives | Reliability |
|---|---|---|---|
| 1 | Cartouche date, where present | Date of the plates | Weak. An upper bound on the plates only, never on the object |
| 2 | Political geography | Terminus post quem from the latest state shown | Strong, where a datable change is legible |
| 3 | Exploratory geography | Bracket from what is shown and what is missing | Moderate. Absence may be omission |
| 4 | Construction and mount | Bracket on the physical object | Weak alone, decisive in combination |
The order is not negotiable. A construction feature that contradicts the cartouche settles nothing on its own, because mounts are replaced; a political boundary that contradicts the cartouche settles the question, because a plate corrected after printing leaves evidence of the correction and an uncorrected plate cannot show a state that did not yet exist.
Of the 48 globes recorded by the Institute from public sale catalogues between March and December 2025, 29 carried a legible cartouche date. In 11 of those 29, the map showed at least one political feature inconsistent with the stated date — in every one of the 11, a feature later than the cartouche. The cartouche was wrong in the same direction every time. A date on a globe is the date of the plates, and the plates went on working.
Construction evidence brackets the sphere itself and, separately, the mount. The two must be bracketed separately, because they are frequently married after the fact — in the 2025 sample, 11 listings stated outright that the mount was later than the sphere, and 14 more gave no date for the mount at all.
As a bracket with the governing evidence named: for example after 1878, before 1901, on political geography; mount not earlier than 1920 on stand type. A single year is never issued. Where the evidence supports no bracket, the Institute publishes none, and 7 of the 48 globes in the 2025 sample were recorded as undatable on the available images.
The Institute has twice been cited as dating a globe by its stand and has published corrections on both occasions. A stand dates the stand. That is the whole of what construction evidence will bear, and it is the point on which this procedure is most often misapplied.