Who was responsible for the development of the rocket motor?

The development of the rocket motor is attributed to several key figures, most notably Konstantin Tsiolkovsky, who conceptualized the rocket equation and the theory of space travel in the early 20th century. However, it was Robert H. Goddard, often called the "father of modern rocketry," who successfully launched the first liquid-fueled rocket in 1926. Additionally, Hermann Oberth, a pioneering rocket scientist, contributed significantly to the theoretical foundations and practical applications of rocket propulsion.