Born on March 19

Cousin and son-in-law of the Prophet Muhammad, Ali ibn Abi Talib was the fourth caliph of Islam (656–661). A central figure of Shia Islam, he is regarded by Shia Muslims as the first rightful imam. His caliphate was marked by the First Fitna, a civil war that gave rise to the foundational Sunni-Shia divide.

King of Aragon, Ferdinand II married Isabella of Castile in 1469, uniting the two great Iberian crowns. Together, the “Catholic Monarchs” completed the Reconquista in 1492, financed Christopher Columbus's voyage, and laid the foundations of modern Spain.

Physician, Protestant missionary, and Scottish explorer (1813–1873), Livingstone was one of the first Europeans to cross Africa from east to west. He contributed to the geographical knowledge of the continent and actively fought against the slave trade.

Wyatt Earp (1848-1929) is an iconic figure of the American conquest of the West. A roving lawman, gambler, and entrepreneur, he owes his fame to the Gunfight at the O.K. Corral in 1881, which became a founding myth of the Wild West.

American social reformer, co-founder with Jane Addams of Hull House in Chicago in 1889. An activist in the Arts and Crafts movement and workers' rights, she worked for popular education and improving the living conditions of immigrants.

Xie Xide (1921-2000) was a Chinese physicist, a pioneer of solid-state physics and semiconductors in China. The first woman to serve as president of Fudan University in Shanghai, she played a major role in the development of modern Chinese physics.