William III (1650-1702) was joint monarch of England with his wife Queen Mary II (1689-1702). He was born in The Hague, the son of the Prince of Orange and Mary, the daughter of Charles I of England. William married Mary, daughter and heir of the Catholic James II in 1677.
In 1688, to prevent King James from re-Catholicising England, seven English peers invited William to invade England. James fled to France. Parliament considered that he had abdicated, but MPs were worried that if his daughter Mary became reigning queen, she could have been considered a usurper. William for his part, had no intention of becoming a King Consort. He had his own uses for England and its resources, as financial aid in his fight to keep Louis XIV of France from invading Holland. William therefore insisted on becoming king and in 1689, he was offered the throne jointly with Mary. The became England's only dual monarchy as William III and Mary II.
Parliament, however, imposed restrictions on their powers through the introduction of constitutional monarchy. The exiled James was still regarded as king in Ireland, but his attempt to win back his crown was stifled by his defeat at the Battle of the Boyne in 1690. The Scots were also curbed by William's forces, though this involved a tragedy. The recalcitrant Scots Highlanders were given until 1st January 1792 to swear allegiance to King William, but Alexander McIan MacDonald of Glencoe was inadvertently late in doing so. The result was a fearful massacre at Glencoe in which forty members of the clan were killed, including MacDonald.
Queen Mary suffered a succession of miscarriages and stillbirths and she and her husband remained childless. Mary died of smallpox in 1694, to the deep grief of her husband. However, with the agreement of Princess Anne, Mary's sister and the next direct heir to the throne, William remained king until his death after a fall from his horse in 1702.