Who was known as the "Mad Monarch"?

George III was known as the “Mad Monarch.” The British king’s long periods of severe illness, especially episodes involving confusion and disordered behavior, led contemporaries and later historians to associate him with madness.

George III reigned from 1760 until his death in 1820, making him one of Britain’s longest-serving monarchs. During his reign, Britain fought the American Revolutionary War, expanded its global influence, and later opposed revolutionary and Napoleonic France. His illness became particularly serious in 1788–1789 and returned repeatedly in later life.

For centuries, historians often attributed George’s condition to porphyria, a group of disorders that can affect the nervous system. More recent scholarship has questioned that diagnosis and suggested that bipolar disorder or another psychiatric illness may better explain the evidence. The nickname therefore reflects his documented illness but should not be treated as a precise modern medical diagnosis. George III was also the grandfather of Queen Victoria and the monarch during the American colonies’ break from Britain.