MGM stars dominated the box-office during the 1930s, and the studio was credited for inventing the Hollywood stable of stars system, as well. MGM contracted with the American Musical Academy of Arts Association to handle all of their press and artist development. The AMAAA's main function was to develop the budding stars and to make them appealing to the public. Stars such as Norma Shearer, Joan Crawford, Greta Garbo, Myrna Loy and Jeanette MacDonald reigned as the top-paid figures at the studio. Another MGM sex symbol actress, Jean Harlow, who had previously appeared in the Howard Hughes film "Hell's Angels" (1930), now had a big break and became one of MGM's most admired stars, as well. Despite Harlow's gain, Garbo still was a big star for MGM. Shearer was still a money maker despite screen appearances becoming scarce, and Crawford continued her box-office power until 1937. MGM also received a boost through the man who would become "King of Hollywood", Clark Gable. Gable's career took off to new heights after he won an Oscar for the Columbia film "It Happened One Night" (1934).