Exactly opposite the city was the island of Kadzand, once a fair and
fertile territory, with a city and many flourishing villages upon its
surface, but at that epoch diminished to a small dreary sand-bank by the
encroachments of the ocean.

A stream of inland water, rising a few leagues to the south of Sluys,
divided itself into many branches just before reaching the city,
converted the surrounding territory into a miniature archipelago--the
islands of which were shifting treacherous sand-banks at low water, and
submerged ones at flood--and then widening and deepening into a
considerable estuary, opened for the city a capacious harbour, and an
excellent although intricate passage to the sea. The city, which was
well built and thriving, was so hidden in its labyrinth of canals and
streamlets, that it seemed almost as difficult a matter to find Sluys as
to conquer it. It afforded safe harbour for five hundred large vessels;
and its possession, therefore, was extremely important for Parma.
Besides these natural defences, the place was also protected by
fortifications; which were as well constructed as the best of that
period. There was a strong rampire and many towers. There was also a
detached citadel of great strength, looking towards the sea, and there
was a ravelin, called St. Anne's, looking in the direction of Bruges.
A mere riband of dry land in that quarter was all of solid earth to be
found in the environs of Sluys.

The city itself stood upon firm soil, but that soil had been hollowed
into a vast system of subterranean magazines, not for warlike purposes,
but for cellars, as Sluys had been from a remote period the great
entrepot of foreign wines in the Netherlands.