The regents found that they had suffered under the powerful leadership of William III and declared the stadtholdership vacant for the second time. The main reason was a quarrel about the title Prince of Orange between John William Friso of the Frisian Nassaus and the King of Prussia. Both descended from Frederick Henry. The King of Prussia, Friedrich I was his grandson through his mother, Louise Henriette of Orange-Nassau. Frederick Henry in his will had appointed this line as successor in the case the House would die out. John William Friso was a great-grandson of Frederick Henry and was appointed heir in William III's will. The solution was that both claimants were allowed to bear the title. The problem of the lands solved itself as the principality of Orange, France was conquered by Louis XIV in 1713. John William Friso drowned in 1711 in the Hollands Diep near Moerdijk, and he left his posthumously-born son William IV. William IV was proclaimed the stadtholder of Guelders, Overijssel, Drenthe, and Utrecht in 1722. When the French invaded Holland in 1747, William was restored as the stadtholder of the entire Dutch Republic, hereditary in both the male and the female lines.