William III and Mary II, a unique dual monarchy in English history, ruled together as king and queen of England, Scotland, and Ireland from 1689 until Mary's death in 1694, after which William ruled alone until his death in 1702.

William, born in 1650, was the son of William II, Prince of Orange, and Mary, the daughter of King Charles I of England. Mary II, born in 1662, was the eldest daughter of King James II of England (James VII of Scotland) and Anne Hyde. Both had a Protestant upbringing. William grew up in the Dutch Republic, a realm known for its Protestant character and its republican values, which would influence his later views on governance.

Mary's early life in England was marked by the shifting religious and political landscape, as her father, James II, was a Roman Catholic, causing tension in a dominantly Protestant England. William and Mary married in 1677, a union that brought together two significant Protestant houses of Europe.

Their joint reign began in the context of the Glorious Revolution. In 1688, alarmed by James II's pro-Catholic policies and the birth of his Catholic heir, seven prominent English nobles invited William to invade England. William's invasion and James II's subsequent flight resulted in a relatively bloodless revolution. In 1689, Parliament offered the crown jointly to William and Mary, stipulating that it would be William who would hold most of the actual power.

Their reign saw the establishment of constitutional monarchy in England. The Bill of Rights in 1689 was a landmark act, setting limits on the powers of the crown and granting specific civil and political rights. This marked a shift in power from the monarchy to Parliament. The Act of Toleration in the same year allowed more religious freedom, though it stopped short of granting full tolerance.

Both William and Mary valued and respected the role of Parliament, and their reign is characterized by a collaborative approach. Their relationship with the governing class was generally positive, with William seeking and often heeding the advice of his ministers.

On foreign relations, William's primary concern was the containment and reduction of the power of Catholic France under Louis XIV. This led to England's participation in several European wars, including the Nine Years' War. These conflicts, while cementing England's Protestant alliances, were costly and not universally popular.

The pair had no children; Mary suffered from several miscarriages, and their lack of an heir was a matter of both personal grief and political concern.

Mary II died of smallpox in 1694, deeply affecting William. His reign after her death saw further strengthening of the parliamentary system and continuity in foreign policy against France. The Act of Settlement in 1701 ensured that if William and his sister-in-law Anne died without heirs, the English crown would pass to the Protestant House of Hanover.

William died in 1702 following a fall from his horse. His death was met with mixed feelings. While some celebrated the end of what they viewed as a foreign reign, others mourned the passing of a king who had secured Protestantism in England and curtailed the absolute ambitions of the monarchy.

Culturally, the reign of William and Mary was a time of growth in commerce, finance, and overseas colonies. The Bank of England was founded in 1694, reflecting the increasing importance of trade and the financial sector. The era also saw the rise of the Whigs and Tories as dominant political parties, shaping the two-party system. Society was marked by a balance between the agrarian traditions and the burgeoning mercantile and financial sectors, laying the groundwork for the transformations of the 18th century.