Length of reign of British monarchs from the House of Windsor 1901-2023

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 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.

George VI and Edward VIII

Preceding Elizabeth II was her father, George VI, who had inherited the throne after the abdication of his brother, Edward VIII, in 1936. Edward became king in May 1936, but just months into his reign he proposed to Wallis Simpson, an American woman who had already been divorced with another pending divorce, and this caused a constitutional crisis. Parliament opposed the marriage as they considered Simpson unfit for the title of Queen Consort, resulting in Edward's abdication.

The House of Saxe-Coburg and Gotha

The House of Windsor has been the reigning royal house since 1901, replacing the House of Hanover, however it was previously named the House of Saxe-Coburg and Gotha. This name was changed to Windsor in 1917, in order to avoid association with Germany during the First World War, taking the name from the royal residence of Windsor Castle. The House of Windsor has ruled during a period of great change in British history, overseeing the expansion of the largest empire in world history in the early 20th century, then over the period of decolonization in the mid-1900s.