William was the only child of William II, Prince of Orange, who died a week before his birth, and Mary, Princess of Orange, the daughter of King Charles I of England. In 1677, during the reign of his uncle King Charles II of England, he married his cousin Mary, the fifteen-year-old daughter of Charles II's brother James, Duke of York. A Protestant, William participated in several wars against the powerful Catholic King Louis XIV of France, in coalition with both Protestant and Catholic powers in Europe. Many Protestants heralded him as a champion of their faith. In 1685, his Catholic uncle and father-in-law, James, became King of England, Scotland and Ireland. James's reign was unpopular with the Protestant majority in Britain, who feared a revival of Catholicism. Supported by a group of influential British political and religious leaders, William invaded England in what became known as the Glorious Revolution. In 1688, he landed at the south-western English port of Brixham. Shortly afterwards, James was deposed.

William's reputation as a staunch Protestant enabled him and his wife to take power. During the early years of his reign, William was occupied abroad with the Nine Years' War (1688–97), leaving Mary to govern the kingdom alone. She died in 1694. In 1696, the Jacobites plotted unsuccessfully to assassinate William and return his father-in-law to the throne. William's lack of children threatened the Protestant succession. The danger was averted by placing distant relatives, the Protestant Hanoverians, in line. Upon his death in 1702 following a serious fall from his horse the king was succeeded by Anne. (Wikipedia article.)

 Anglo-Irish Coins

Up until 1696 most of the coinage in circulation was old clipped and worn hammered silver; this was replaced by a great re-coinage, with provincial mints temporarily operating in Bristol, Chester, Exeter, Norwich and York.  Silver coins with roses between the coats of arms on the reverse were struck from silver from the West of England mines.  The Bank of England was formed during William's reign.