Leibniz's 'Nova Methodus pro Maximis et Minimis' introduced his notation for derivatives, laying groundwork for modern calculus independently of Newton's earlier but unpublished work. The rival claims of invention sparked a bitter, decades-long controversy between British and continental mathematicians that shaped the development of European science.
Leibniz had developed his differential calculus in Paris in the 1670s, arriving at many of the same conclusions Isaac Newton had reached years earlier in England but had not published. When Leibniz's paper appeared in the journal Acta Eruditorum, it introduced the elegant dy/dx notation still used by students today, in contrast to Newton's clunkier dot notation for fluxions.
The question of who deserved credit metastasized into one of the most notorious priority disputes in the history of science. The Royal Society, presided over by Newton himself, eventually issued a report in 1712 accusing Leibniz of plagiarism—a verdict now regarded as biased and largely discredited by historians.
The rift split European mathematics along national lines for a generation: British mathematicians clung loyally to Newton's clumsier notation and fell behind continental colleagues who adopted Leibniz's more powerful and flexible system, which proved far better suited to solving complex problems.