At the turn of the 18th century, mathematics was exploding with new ideas. Calculus had just been invented. Guillaume de l’Hôpital was a wealthy French nobleman passionate about math, but not exactly a genius. He hired one of the brightest young mathematicians of the time, Johann Bernoulli, as a personal tutor. Bernoulli was so talented that L’Hôpital made him an incredible offer: a yearly salary of 300 francs in exchange for every new discovery he made. Yes, L’Hôpital bought theorems. Whenever Bernoulli found something new, he sent it to his employer. In 1696, L’Hôpital published the first calculus textbook, Analyse des Infiniment Petits. It introduced the famous L’Hôpital’s Rule, how to handle indeterminate limits like 0/0. But here’s the twist: the rule, and much of the book, were actually written by Bernoulli. After L’Hôpital’s death, Bernoulli revealed the truth and showed the letters proving the arrangement. Still, L’Hôpital’s name stayed attached to the rule—a reminder that sometimes in science, money buys fame. Today, every calculus student learns L’Hôpital’s Rule, even if the real author was Johann Bernoulli.