The Whigs (Whig party) were a political group 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 was in constitutional monarchism and opposition to absolute monarchy. They played a big part in the Glorious Revolution of 1688. They were the 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 came to the throne in 1760.
Later on, many of their ideas were adopted by the Liberal Party in the later 19th century.