Born on April 5

A 17th-century English philosopher, Thomas Hobbes is the author of Leviathan (1651), a founding work of modern political philosophy. He develops a social contract theory justifying the absolute authority of the state to guarantee peace and security.

Vincenzo Viviani was an Italian mathematician and physicist, the last disciple and assistant of Galileo. He worked to preserve and publish his master's scientific legacy and contributed to geometry and the study of motion.

Katharina Gsell (c. 1707–1773) was the daughter of Swiss painter Georg Gsell, who was employed at the imperial court of Saint Petersburg. In 1734 she married the mathematician Leonhard Euler, one of the greatest scholars of the 18th century, and was the companion of his entire scientific life.

French painter and engraver of the 18th century, a major figure of the Rococo style. Renowned for his amorous scenes full of virtuosity and lightness, he embodies the refined art of the waning Ancien Régime.

French statesman (1832–1893) who transformed French education as Minister of Public Instruction. He is responsible for the landmark education laws making primary school free, secular, and compulsory, laying the foundations of the modern French public school system.

Albert Roussel was a French composer, one of the major figures of French music in the early 20th century. A former naval officer who became a musician, he developed a personal style blending impressionism and neoclassicism.

Spencer Tracy (1900-1967) was one of the most respected actors of Hollywood's golden age. Known for his natural, understated acting, he was the first performer to win two consecutive Academy Awards for Best Actor and formed a famous duo, both on screen and in real life, with Katharine Hepburn.

American actress (1908–1989), a towering figure of Hollywood cinema from the 1930s through the 1960s. Known for her roles as strong, complex women, she won two Academy Awards and established herself as one of the greatest stars of the studio system.

Luke Yuan is a 21st-century scientist whose contributions fall within the field of contemporary science. His career path illustrates the internationalization of global scientific research.