A 10-year-old Sikh maharaja signed away the Koh-i-Noor to Queen Victoria, and other countries still claim it

Duleep Singh became ruler of the Sikh Empire at five in 1843, the youngest son of Maharaja Ranjit Singh, who had owned the Koh-i-Noor diamond. After the Second Anglo-Sikh War, the East India Company annexed the Punjab. The Treaty of Lahore of 29 March 1849, signed in Duleep's name when he was ten, required the Koh-i-Noor to be surrendered to the Queen of England. The diamond was presented to Victoria in 1850 and recut in 1852, losing about 40 percent of its weight. Duleep was separated from his mother, converted to Christianity and lived as a country squire in Suffolk on a British pension. In later life he tried to reclaim his inheritance, reconverted to Sikhism and died in a Paris hotel in 1893. The diamond is set in the crown of Queen Elizabeth the Queen Mother in the Tower of London. India, Pakistan, Afghanistan and Iran have claimed it^†. Queen Camilla did not wear it at the 2023 coronation.