Vlissingen on the island of Walcheren had a well-defended naval base and was strategically located at the mouth of the Scheldt estuary, guarding the entrance to the key port of Antwerp. The town and the area of Dutch Flanders to the south were part of the province of Zeeland in the Dutch Republic until the region was occupied by the French in 1795, during the French Revolutionary Wars. Under the terms of the Treaty of The Hague in May of that year, which concluded the war between the French and Dutch, Dutch Flanders was ceded to France, while Vlissingen was placed under French-Dutch co-dominion, and the French were allowed to station a garrison at Vlissingen.