John William Friso, Prince of Orange-Nassau (Dutch: Johan Willem Friso van Oranje-Nassau) became the titular Prince of Orange in 1702. He was stadtholder of Friesland until his death by drowning in the Hollands Diep in 1711. Friso and his wife, Marie Louise, are the most recent common ancestors of all European monarchs occupying the throne today.
He was the son of Henry Casimir II, Prince of Nassau-Dietz, and Princess Henriëtte Amalia of Anhalt-Dessau who were both first cousins of William III. As such, he was a member of the House of Nassau (the branch of Nassau-Dietz), and through the testamentary dispositions of William III became the progenitor of the new line of the House of Orange-Nassau.
With the death of William III, Prince of Orange, the legitimate male line of William the Silent (the second House of Orange) became extinct. John William Friso, the senior agnatic descendant of William the Silent's brother and a cognatic descendant of Frederick Henry, grandfather of William III, claimed the succession as stadtholder in all provinces held by William III. This was denied to him by the republican faction in the Netherlands.
The five provinces over which William III ruled - Holland, Zeeland, Utrecht, Gelderland and Overijssel - all suspended the office of Stadtholder after William III's death. The remaining two provinces – Friesland and Groningen - were never governed by William III, and continued to retain a separate Stadtholder, John William Friso. He established the third House of Orange, which became extinct in the male line in 1890. His son William IV, Prince of Orange, however, later became stadtholder of all seven provinces.
In 1711, when traveling from the front in Flanders to meet the King of Prussia in The Hague in connection with his suit in the succession dispute, he drowned on 14 July when the ferry boat on the Moerdyk was overturned in heavy weather. His son was born six weeks after his death.