Here is the Dartmouth Corporation seal that appears on the Royal Charter
that
Edward III granted the city in 1341.
The King wanted to reward Dartmouth merchants for supplying him with ships
of war for his military campaigns in France. Fittingly, the seal depicts
the King riding in a cog (merchant ship) typically used at the time. Note
the image's similarity to the
gold noble
of Edward III.
You may also wish to take a look at the corporation seal of the city of
London.