Born on March 11

Queen of France and regent, Blanche de Castille (1188–1252) governed the kingdom during the minority of her son Louis IX (Saint Louis) and again during his crusade. A woman of exceptional power, she successfully asserted royal authority against the great barons.

Louis Bachelier was a French mathematician who pioneered the modern theory of probability applied to finance. His 1900 thesis on stock market speculation introduced Brownian motion before Einstein, founding the field of financial mathematics.

Argentine composer and bandoneon player (1921–1992), Astor Piazzolla revolutionized traditional tango by creating "tango nuevo," a fusion of tango, jazz, and classical music. He is considered one of the most influential musicians in 20th-century Latin America.

French philosopher, economist, and psychoanalyst of Greek origin, co-founder of the group and journal Socialisme ou Barbarie. A thinker of autonomy and the social imaginary, he developed a radical critique of Marxism and bureaucracies.