Length of reign of British monarchs from the House of Windsor 1901-2023
longest reigning monarch in British and English history. At 73 years old, Charles III was the oldest person to become monarch, having served as the longest heir apparent in British history. The current heir apparent is Prince William, who will likely become King William V.
Britain is classified as a constitutional monarchy, which means that power is shared between the ruling head of state (i.e. the king or queen) and an elected Parliament. The current head of state is King Charles III, who ascended to the throne following the death of his mother, Elizabeth II, in September 2022. Elizabeth II reigned for over 70 years, making her the