During this Golden Age, the studio was a factory churning out "product." MGM, under the stewardship of Louis B. Mayer, became synonymous with glamour and musicals, producing cultural touchstones like The Wizard of Oz and Singin' in the Rain . Warner Bros. carved out a grittier identity with gangster films and social dramas. This era established the brand identities that, in some cases, persist to this day.