William II, Prince of Orange in the context of "United Provinces of the Netherlands"

William III and II (William Henry; Dutch: Willem Hendrik; 4 November 1650 – 8 March 1702), also known as William of Orange, was the sovereign Prince of Orange from birth, Stadtholder of Holland, Zeeland, Utrecht, Guelders, and Overijssel in the Dutch Republic from 1672, and King of England, Ireland, and Scotland from 1689 until his death in 1702. He ruled England, Scotland, and Ireland with his wife, Queen Mary II, and their joint reign is known as that of William and Mary.

William was the only child of William II, Prince of Orange, and Mary, Princess Royal, the daughter of King Charles I of England, Scotland, and Ireland. His father died before his birth, making William III the prince of Orange from birth. In 1677, he married his first cousin Mary, the elder daughter of his maternal uncle James, Duke of York (later King James II).

Frederick Henry (Dutch: Frederik Hendrik; 29 January 1584 – 14 March 1647) was the sovereign prince of Orange and stadtholder of Holland, Zeeland, Utrecht, Guelders, and Overijssel in the Dutch Republic from his older half-brother's death on 23 April 1625 until his death on 14 March 1647. In the last seven years of his life, he was also the stadtholder of Groningen (1640-1647).

As the leading soldier in the Dutch wars against Spain, his main achievement was the successful Siege of 's-Hertogenbosch in 1629. It was the main Spanish base and a well-fortified city protected by an experienced Spanish garrison and by formidable water defenses. His strategy was the successful neutralization of the threat of inundation of the area around 's-Hertogenbosch' and his capture of the Spanish storehouse at Wesel. The successful sieges under his command earned him the epithet ‘city forcer’ (Dutch: stedendwinger). He was the paternal grandfather of William III, who later became King of England, Scotland & Ireland, through his only surviving son, William II.

Sir Constantijn Huygens, Lord of Zuilichem (/ˈhaɪɡənz/ HY-gənz, US also /ˈhɔɪɡənz/ HOY-gənz, Dutch: [ˈkɔnstɑntɛin ˈɦœyɣə(n)s]; 4 September 1596 – 28 March 1687), was a Dutch Golden Age poet and composer. He was also secretary to two Princes of Orange: Frederick Henry and William II, and the father of the scientist Christiaan Huygens.