On
30 August 1944, Montgomery ordered Gen. Horrocks of XXX Corps to mount an attack and take Antwerp. Horrocks was on the Seine River at this time.
...
On 4 September 1944, XXX Corps reaches Antwerp, and with the help of the Belgian resistance the city was secured and the port facilities were captured intact. The advance was halted at Antwerp...
The Scheldt estuary, which connects the North sea with Antwerp, was 80km long and in Dutch territory.
The Germans held both sides of the estuary...
On 17 September 1944, Market-Garden was launched.