Leibnitz played an important role, and was better at tooting his own horn, and publishing, but Newton was the one who came up with the idea.
"Leibnitz played an important role, and was better at tooting his own horn, and publishing, but Newton was the one who came up with the idea."
Maybe in the comic book version. But the idea had been around for centuries, probably back to the Egyptians. The Greek paradox of Achilles and the Hare (and the numerous variations) speaks to it.
It was very much a group effort. There was a group of Englishmen who really got it going, in the mid-1600s. Then Newton and Leibnitz (working entirely independently, but parallel) came up with some major advances.
But it really took a couple guys even after them (like Cauchy) to polish the calculus into what we know today.