Catherine Colyear, suo jure Countess of Dorchester and Countess of Portmore, was an English noble and courtier. She was the mistress of King James II of England both before and after he came to the throne. Catherine was noted not for beauty but for her celebrated wittiness and sharp tongue.

James VII and II was King of England and Ireland as James II and King of Scotland as James VII from the death of his elder brother, Charles II, on 6 February 1685. He was deposed in the Glorious Revolution of 1688. He was the last Catholic monarch of England, Scotland, and Ireland. His reign is now remembered primarily for conflicts over religious tolerance, but it also involved struggles over the principles of absolutism and the divine right of kings. His deposition ended a century of political and civil strife in England by confirming the primacy of the English Parliament over the Crown.