This is only likely supposition. Jacob Karstensen was probably captain of a small fishing boat, possibly Danish where his surname is common. Probably worked the North Sea and it was not uncommon for them to form a relationship with someone from and other country whist in overseas port. Anna Jacobs seems like an English name and would have been his wife. They had this plate ordered to commemorate their union on 28th November 1783.
Diameter: 9 ⅝”
In good condition