While the peace negotiations were progressing at a snail's pace, Frederick Henry managed a last few military successes: in 1644 he captured Sas van Gent and Hulst in what was to become States Flanders. In 1646, however, Holland, sick of the feet-dragging in the peace negotiations, refused to approve the annual war budget, unless progress was made in the negotiations. Frederick Henry now gave in and began to promote the peace progress, instead of frustrating it. Still, there was so much opposition from other quarters (the partisans of France in the States General, Zeeland, Frederick Henry's son William) that the peace could not be concluded before Frederick Henry's death on 14 March 1647.