Duleep Singh was the last Maharaja of the Sikh Empire, and the owner of the Koh-I-Noor, a 105.6-carat diamond. The Koh-I-Noor, meaning "mountain of light," was likely one of the treasures of India's Mughal Empire, and has passed from group to group over the last few centuries of volatility and warfare in South Asia.
In 1850, the British East India company's colonial government in India forced Duleep Singh into exile in London. Once there, he "gave" the Koh-I-Noor to Queen Victoria. Today, it is set in a crown once worn by the late Queen Mother, but the heirs of Duleep Singh are pressing the British government to return the confiscated treasure.
Photo of the Queen Mother's crown, topped by the Koh-I-Noor diamond, by Anthony Harvey / Getty Images.