King George III was the monarch of Great Britain and Ireland from 1760 until his death in 1820. He was known for his long reign, which saw significant events like the American Revolution and the Napoleonic Wars. George III was known for his struggle with mental illness, which led to regency being granted to his son. Despite this, he played an influential role in shaping British domestic and foreign policies during a crucial period in history. His legacy is a complex mix of accomplishments and controversies.