Profession: mathematician

Bernoulli, a significant mathematician even in that family of mathematicians, is known as an early proponent of calculus. Jacob was his elder brother, who taught and worked with him closely, and whose university position he inherited. Daniel was his son; he developed a jealously competitive relationship with both. He tutored Euler (whose father was a friend, and who corresponded for 14 years), also teaching König, Haller and Maupertuis (who lodged with him). The aristocratic de l’Hôpital paid him handsomely, and published Bernoulli’s work as if his own. Leibniz, one of the founders of calculus, corresponded extensively about it.

Voltaire, who’d known her as a child, was her lover and intellectual companion for 15 years, following her relationships with Maupertuis (who’d been her mathematics tutor) and Clairaut. She and Voltaire used English to argue in. She consulted Buffon over her translation of Newton’s ‘Principia’, and corresponded with Bernoulli, a friend. König travelled to Brussels with Châtelet and Voltaire, and seems to have been one of the few mathematicians she had a major disagreement with.

Goldbach is notable for his work on number theory. On a decade-and-a-half journey around Europe, he met Moivre in London, Leibniz in Leipzig (they continued to correspond), and Nicolaus Bernoulli in Venice, who suggested Goldbach contact his brother Daniel — they corresponded for 7 years. Euler became a colleague in St Petersburg; they started a 35-year correspondence. In one of his letters, Goldbach outlined the conjecture now famously named after him; characteristically, Euler tested its validity substantially further than Goldbach, who tended to be more interested in the ideas than the hard work.