Cloth Seal, Dutch?, Hoorn?

Cloth Seal, Dutch, Hoorn?, Image & Found by Herman Vos.
Found in Vinkeveen, Netherlands, 20mm.

Postal horn // missing but partial stamp of castle gate on rivet stub

A cloth seal possibly from Hoorn, "a municipality and a town in the Netherlands, in the province of North Holland."
Not to be confused with Horn (Limburg) which has three horns on its coat of arms.

The castle could suggest Germany or even England.