British Museum curators concur with monty,
"...based upon the
type of costumes worn by the indivduals depicted on the button, we would look to date the object to the late 18th century at the earliest. With particular reference to the
style of hat shown on the button, these were commonly known as 'Chapeau bras' and they became popular for formal dress in the 1780s - their most famous wearer was a one Napoloean Bonaparte. Having said this, there is also a chance that the button could be a copy of an earlier example and therefore, this would push its date of production to the early to mid 19th century.
The lack of an obvious means of attachment should not concern us as certain
types of buttons were constructed to sit in a case shell which would have the means to attach to a particular item of clothing - this case shell therefore, could easily have become loose over the years through wear and tear and become detached from the button and lost."
hi, this looks very much like the decorative front of an early 19th century pressed button.
the figures look very napoleonic.
regards, monty