Who discovered rocket fuel?

Rocket fuel, in various forms, has been developed over centuries by numerous scientists and engineers. Notably, Konstantin Tsiolkovsky, a Russian pioneer of astronautics, contributed significantly to the theoretical foundations of rocket propulsion in the early 20th century. However, the first liquid rocket fuel was successfully used by Robert H. Goddard in 1926 when he launched the world's first liquid-fueled rocket. The development of solid rocket fuels also involved many contributors, including the Chinese, who developed gunpowder-based rockets centuries earlier.