William III of the Netherlands was the king of the Netherlands for four decades from 1849 to 1890. The son of King William II and Anna Pavlovna of Russia, he ascended to the throne after the death of his father. The king’s behavior was often erratic, and it is speculated he suffered from a mental disorder.
William I of the Netherlands reigned as the king of the Netherlands from 1815 to 1840. Before declaring himself King of the Netherlands, William I had an influential career in the military. In 1790, he was made the Dutch States Army's general of infantry where he served under his father William V, who served as Captain-General.
William II took over as the king of the Netherlands after his father William I’s abdication. His reign witnessed the transformation of his country into a parliamentary democracy through the constitution of 1848. With F.A. van Hall as the finance minister, he helped his country attain a surplus.
William V, Prince of Orange served as the last stadtholder of the United Provinces of the Netherlands from 1751 to 1795. He also ruled the Principality of Orange-Nassau from 1751 until his death on 9 April 1806.
Prince Bernhard of Lippe-Biesterfeld was a German-born nobleman who achieved popularity after marrying Queen Juliana of the Netherlands. The couple had four children including Beatrix who served as the Queen of the Netherlands between 1980 and 2013. Bernhard is also remembered for his work as a combat pilot during World War II. He also helped establish the World Wildlife Fund.
Henry VI of the Hohenstaufen dynasty was the Holy Roman Emperor in the 12th century. He was also the king of Germany and of Sicily, the latter through his marriage to Constance I. He failed in his attempt to make the crown of the Holy Roman Emperor a hereditary monarchy.
John William Friso, the Prince of Orange, succeeded William III of Orange as the stadtholder of the provinces of Friesland and Groningen in the Dutch Republic and remained so until his death. Friso along with his wife, Marie Louise, is noted as the most recent common ancestors of all the currently reigning European monarchs.