Herb Jeffries (born Umberto Alexander Valentino; September 24, 1913 - May 25, 2014) was an African-American actor of film and television and popular music and jazz singer-songwriter, known of his baritone voice. He was of African descent and Hollywood's first singing black cowboy. In the 1940s and 1950s Jeffries recorded for a number of labels, including RCA Victor, Exclusive, Coral, Decca, Bethlehem, Columbia, Mercury and Trend. His album Jamaica, recorded by RKO, is a concept album of self-composed calypso songs.

Touring the Deep South with Hines, Jeffries was struck by the realities of segregation, as the Orchestra's playing was restricted to tobacco warehouses and black-only movie theatres. Watching young boys fill theatres to watch the latest western, Jeffries resolved to create a cowboy hero geared specifically for such an audience. A self-confessed western buff who had grown up watching the silent escapades of Tom Mix and Jack Holt, in the 1930s Jeffries set out to produce a low-budget western with an all-black cast. Though the silent era had seen a number of films starring only black actors, they had all but disappeared with the economic downturn and the arrival of the talkies, which proved too expensive for many of the "white independents" funding such projects. Jeffries's ambition was to produce sound cinema's "first all-Negro musical western". To fund his project, Jeffries approached a veteran B-movie producer named Jed Buell. Jeffries, having obtained finances, wrote his own songs for the film and hired Spencer Williams to appear with him. When Buell wanted to know of a likely candidate for the lead role, Jeffries nominated himself. Having grown up partly on his grandfather's farm, he had all the requisite horse-riding and roping skills, beside a fine singing voice, but Buell expressed concerns; Jeffries, whose mother was of Irish descent, was "not black enough". Eventually they went ahead, using make-up to darken the leading man's skin tone. Jeffries made his debut as a crooning cowboy with Harlem on the Prairie, which was considered the first black western following the inauguration of the talkies and the first sound Western with an all-black cast. The movie was shot in 1937 over five days at N.B. Murray's Dude Ranch in Apple Valley, California, with Jeffries performing all his own stunts. Though critical reception was mixed, the film received a write-up in Time magazine and grossed $50,000 in its first 12 months. Playing a singing cowboy in low-budget films, Jeffries became known as the "Bronze Buckaroo" by his fans. In a time of American racial segregation, such "race movies" played mostly in theaters catering to African-American audiences. The films include Harlem on the Prairie, The Bronze Buckaroo, Harlem Rides the Range and Two-Gun Man from Harlem.  Jeffries went on to star in another three musical westerns over the next two years. Jeffries starred as a singing cowboy, in several all-black Western films, in which he sang his own western compositions. In those films, Jeffries starred as cowboy Bob Blake, sang and performed his own stunts. Bob Blake was the good guy, with a thin mustache, who wore a white Stetson and rode a white horse named Stardusk.  Jeffries went on to make other films, starring in the title film role of Calypso Joe co-starring Angie Dickinson in Calypso Joe (1957). In 1968, Jeffries appeared in the long-running western TV series The Virginian playing a gunslinger who intimidated the town. In the 1970s he appeared on episodes of I Dream of Jeannie and Hawaii Five-0. He later directed and produced Mundo depravados, a cult film starring his wife, Tempest Storm.

Using a quote from the above article, answer the following question: when did his film career begin
Holt, in the 1930s Jeffries set out to produce a low-budget western with an all-black cast.