Write a date when the date is uncertain

An uncertain date should show both the estimate and its basis. Precision is useful only when the evidence supports it.

Start by recording what is actually available: an inscription, dated receipt, catalogue range or a person's recollection. Keep the original wording. A date written on the back of a photograph may refer to the event, the print or a later annotation, so record its location and appearance without assuming which it means.

Use a range honestly

If evidence places an object between two dates, state the range and explain why. Do not choose the midpoint merely because a form requests one year. Use the system's uncertainty fields or a clear note when a single date is unavoidable for sorting.

Distinguish a manufacturing date from acquisition, use and later repair. These can all be relevant and should not compete for one unexplained box labelled date. Keep the source reference beside each claim.

When new evidence narrows the range, update the record while retaining the earlier estimate and reason. A transparent change is better than a precise date that appears to have always been known. The reader should be able to understand what is dated, how securely it is dated and what remains uncertain without deciphering a code hidden in the catalogue.