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.