Birth and family
William III was born in The Hague in the Dutch Republic on 4 November 1650. Baptised William Henry (Dutch: Willem Hendrik), he was the only child of stadtholder William II, Prince of Orange, and Mary, Princess Royal. Mary was the eldest daughter of King Charles I of England, Scotland and Ireland and sister of King Charles II and King James II and VII.
Eight days before William was born, his father died of smallpox; thus William was the Sovereign Prince of Orange from the moment of his birth. Immediately, a conflict ensued between his mother the Princess Royal and William II's mother, Amalia of Solms-Braunfels, over the name to be given to the infant. Mary wanted to name him Charles after her brother, but her mother-in-law insisted on giving him the name William or Willem to bolster his prospects of becoming stadtholder. William II had appointed his wife as his son's guardian in his will; however, the document remained unsigned at William II's death and was void. On 13 August 1651, the Hoge Raad van Holland en Zeeland (Supreme Court) ruled that guardianship would be shared between his mother, his paternal grandmother and Frederick William, Elector of Brandenburg, whose wife, Louise Henriette, was William II's eldest sister.
Childhood and education
William's mother showed little personal interest in her son, sometimes being absent for years, and had always deliberately kept herself apart from Dutch society. William's education was first laid in the hands of several Dutch governesses, some of English descent, including Walburg Howard and the Scottish noblewoman, Lady Anna Mackenzie. From April 1656, the prince received daily instruction in the Reformed religion from the Calvinist preacher Cornelis Trigland, a follower of the Contra-Remonstrant theologian Gisbertus Voetius. The ideal education for William was described in Discours sur la nourriture de S. H. Monseigneur le Prince d'Orange, a short treatise, perhaps by one of William's tutors, Constantijn Huygens. In these lessons, the prince was taught that he was predestined to become an instrument of Divine Providence, fulfilling the historical destiny of the House of Orange-Nassau.
From early 1659, William spent seven years at the University of Leiden for a formal education, under the guidance of ethics professor Hendrik Bornius (though never officially enrolling as a student). While residing in the Prinsenhof at Delft, William had a small personal retinue including Hans Willem Bentinck, and a new governor, Frederick Nassau de Zuylenstein, who (as an illegitimate son of stadtholder Frederick Henry of Orange) was his paternal uncle.
Grand Pensionary Johan de Witt and his uncle Cornelis de Graeff pushed the States of Holland to take charge of William's education and ensure that he would acquire the skills to serve in a future—though undetermined—state function; the States acted on 25 September 1660. This first involvement of the authorities did not last long. On 23 December 1660, when William was ten years old, his mother died of smallpox at Whitehall Palace, London, while visiting her brother, the recently restored King Charles II. In her will, Mary requested that Charles look after William's interests, and Charles now demanded that the States of Holland end their interference. To appease Charles, they complied on 30 September 1661. That year, Zuylenstein began to work for Charles and induced William to write letters to his uncle asking him to help William become stadtholder someday. After his mother's death, William's education and guardianship became a point of contention between his dynasty's supporters and the advocates of a more republican Netherlands.
The Dutch authorities did their best at first to ignore these intrigues, but in the Second Anglo-Dutch War one of Charles's peace conditions was the improvement of the position of his nephew. As a countermeasure in 1666, when William was sixteen, the States officially made him a ward of the government, or a "Child of State". All pro-English courtiers, including Zuylenstein, were removed from William's company. William begged De Witt to allow Zuylenstein to stay, but he refused. De Witt, the leading politician of the Republic, took William's education into his own hands, instructing him weekly in state matters and joining him for regular games of real tennis.