The Watermarks Database includes images of each watermark as well as, where known,
other useful information: date of manufacture, date of usage, provenance, sheet
thickness and details of the mill or firm that made the sheet.
The dates given are from a range of sources: some watermarks include a date of manufacture,
in other cases the document is dated, or the file it came from is dated. Where there
is a range of dates given it indicates that we have seen a number of examples over
this range, a single date indicates we have only seen one example of this watermark.