In 1639, Ferdinand managed again to thwart Franco-Dutch plans. The Dutch navy defeated an important Spanish fleet in the Battle of the Downs, off the English coast, but it failed to prevent most of the army it was carrying, some 7,000 to 10,500 infantry, from landing at Dunkirk. While Ferdinand frustrated the Prince of Orange's move against Hulst, a Spanish army under Count Piccolomini destroyed the main French army in the south at the Battle of Thionville.