Bergen op Zoom is a municipality and a city located in the south of the Netherlands.
It was a very strong fortress and one of the main armories and arsenals of the United Provinces. It had a remarkable natural defensive site, surrounded as it was by marshes and easily floodable polders. It could receive reinforcements and supplies by sea, if the besieging army did not have a fleet to blockade its port. – Wikipedia.
Background from Wikipedia.