Gaston Julia (1893-1978) was a French mathematician who published a book on the iteration of rational functions in 1918. Before computers, he had to draw the sets of functions by hand. These types of fractals are now called Julia sets.

Benoit Mandelbrot (1924-2010) is an emeritus professor at Yale University. He used a computer to explore Julia's iterated functions, and found a simpler equation that included all the Julia sets. This Mandelbrot set is named after him.