Jean le Rond d'Alembert (1717–1783) was a French mathematician, physicist and one of the great minds of the Enlightenment. He got his first name from the little Paris church, Saint-Jean-le-Rond, on whose steps he was found as an abandoned baby — and grew up to become one of the most celebrated thinkers in Europe.
d'Alembert was the first to really understand the vibrating string, and he wrote down the wave
equation and its beautiful answer:
d'Alembert's story is pure novel. He was the secret child of an aristocratic mother, who wanted nothing to do with him, and an artillery officer, who quietly arranged for him to be raised by a humble glazier's family — and paid for his schooling. When d'Alembert became famous, his birth mother reappeared to claim him; he is said to have coolly replied that the glazier's wife was his real mother. He stayed loyal to the modest home that actually loved him and shrugged off the grand family that hadn't.