The Whigs were a political faction and then a political party in the parliaments of England, Scotland, Great Britain, Ireland and the United Kingdom. Between the 1680s and 1850s, they contested power with their rivals, the Tories. The Whigs' origin lay in constitutional monarchism and opposition to absolute monarchy. The Whigs played a central role in the Glorious Revolution of 1688 and were the standing enemies of the Stuart kings and pretenders, who were Roman Catholic. The Whigs took full control of the government in 1715 and remained totally dominant until King George III, coming to the throne in 1760, allowed Tories back in. The Whig Supremacy (1715–1760) was enabled by the Hanoverian succession of George I in 1714 and the failed Jacobite rising of 1715 by Tory rebels. The Whigs thoroughly purged the Tories from all major positions in government, the army, the Church of England, the legal profession and local offices. The Party's hold on power was so strong and durable, historians call the period from roughly 1714 to 1783 the age of the Whig Oligarchy. The first great leader of the Whigs was Robert Walpole, who maintained control of the government through the period 1721–1742 and whose protégé Henry Pelham led from 1743 to 1754.
Both parties began as loose groupings or tendencies, but became quite formal by 1784 with the ascension of Charles James Fox as the leader of a reconstituted Whig Party, arrayed against the governing party of the new Tories under William Pitt the Younger. Both parties were founded on rich politicians more than on popular votes, and there were elections to the House of Commons, but a small number of men controlled most of the voters.
The Whig Party slowly evolved during the 18th century. The Whig tendency supported the great aristocratic families, the Protestant Hanoverian succession and toleration for nonconformist Protestants (the dissenters, such as Presbyterians), while some Tories supported the exiled Stuart royal family's claim to the throne (Jacobitism) and virtually all Tories supported the established Church of England and the gentry. Later on, the Whigs drew support from the emerging industrial interests and wealthy merchants, while the Tories drew support from the landed interests and the royal family. However, by the first half of the 19th century the Whig political programme came to encompass not only the supremacy of parliament over the monarch and support for free trade, but Catholic emancipation, the abolition of slavery and expansion of the franchise (suffrage). The 19th century Whig support for Catholic emancipation was a complete reversal of the party's historic sharply anti-Catholic position at its late 17th century origin.
The term "Whig" was originally short for "whiggamor", a term meaning "cattle driver" used to describe western Scots who came to Leith for corn. In the reign of Charles I the term was used during the Wars of the Three Kingdoms to refer derisively to a radical faction of the Scottish Covenanters who called themselves the "Kirk Party" (see the Whiggamore Raid). It was then applied to Scottish Presbyterian rebels who were against the King's Episcopalian order in Scotland. The term "Whig" entered English political discourse during the Exclusion Bill crisis of 1678–1681 when there was controversy about whether or not King Charles II's brother, James, should be allowed to succeed to the throne on Charles's death. "Whig" was a term of abuse applied to those who wanted to exclude James on the grounds that he was a Roman Catholic. The fervent Tory Samuel Johnson often joked that "the first Whig was the Devil".