Carl Jung attributed his split with his mentor Sigmund Freud around 1910 in part to a generational divide. “Our descendants are our most dangerous enemies,” Jung argued, “for they will outlive us, and, therefore, without fail, will take the power from our enfeebled hands.”

Dynamite magnate Alfred Nobel omitted mathematics from the final list of categories his prizes would specifically recognize, claiming the prize for physics would cover it. Rumors circulated—likely helped along by the miffed Gösta Mittag-Leffler, Sweden’s leading mathematician—that this was due to a romantic rivalry between Nobel and Mittag-Leffler; the woman had chosen the mathematician, and punishing the whole field was Nobel’s revenge.

In love with the same slave girl, Iris, two men in first-century Pompeii fought via graffiti. Severus tagged the wall first, writing that Iris did not love Successus, adding, “His rival wrote this.” Successus responded, “Don’t even think to speak badly of a man more handsome than you, especially one who is both most vicious when crossed and yet also good.” “I have written all there is to say,” Severus retorted. “You love Iris, but she does not love you.”

In 1873, as part of the Bone Wars, paleontologist Othniel Charles Marsh complained in The American Naturalist that his rival, Edward Drinker Cope, was dentally inept; he “mistook canines for incisors, nasals for frontals, maxillaries for premaxillaries, maxillaries for nasals, and maxillaries for frontals!” Cope claimed he was “too fully occupied on more important subjects.”