William of Orange was a sovereign prince before he was born
William III's father died of smallpox eight days before his birth in 1650, so the baby arrived already Prince of Orange. He grew up to spend his life resisting Louis XIV of France, and in 1688 led a Dutch invasion of England that ended with him and his wife Mary sharing its throne.
Born in The Hague, William was the only child of the Dutch stadtholder William II and Mary, daughter of England's Charles I. Even his name was a fight: his mother wanted to call him Charles after her brother, while his paternal grandmother insisted on William to strengthen his claim to Dutch office. His father's will naming Mary as guardian had never been signed, so a court split guardianship three ways. His mother took little interest in him and was sometimes away for years, and his tutors raised him to believe he was an instrument of divine providence, heir to William the Silent.
When France invaded the Dutch Republic in 1672, the young prince took power and rebuilt a shattered army into one of Europe's most professional forces. Checking Louis XIV became his life's purpose. In 1677 he married his first cousin Mary, elder daughter of James, Duke of York.
That uncle became King James II in 1685, and his Catholicism, rule by decree and the prospect of a Catholic succession alarmed English Protestants. Invited by a group of influential English leaders, William landed at Brixham in November 1688 with a Dutch force. James was quickly deposed, and William and Mary were offered the crown together in what became known as the Glorious Revolution, which produced the English Bill of Rights.
As king he spent much of his time fighting France in the Nine Years' War, leaving Mary to govern until her death in 1694. He survived a Jacobite assassination plot in 1696, and in Scotland his part in ordering the Massacre of Glencoe remains notorious. With no children, and his nephew the Duke of Gloucester dead in 1700, he secured a Protestant future through the Act of Settlement of 1701, placing the House of Hanover in line after Mary's sister Anne, who succeeded him in 1702.
Source: William III of England
