Richard I, known as Richard Cœur de Lion or Richard the Lionheart because of his reputation as a great military leader and warrior, was King of England from 1189 until his death in 1199. He also ruled as Duke of Normandy, Aquitaine, and Gascony; Lord of Cyprus; Count of Poitiers, Anjou, Maine, and Nantes; and was overlord of Brittany at various times during the same period. He was the third of five sons of Henry II of England and Eleanor of Aquitaine and was therefore not expected to become king, but his two elder brothers predeceased their father.

The monarchy of the United Kingdom, commonly referred to as the British monarchy, is the form of government used by the United Kingdom by which a hereditary monarch reigns as the head of state, with their powers regulated by the British Constitution. The term may also refer to the role of the royal family within the UK's broader political structure. The current monarch is King Charles III, who ascended the throne on 8 September 2022, upon the death of his mother, Queen Elizabeth II.