Phillip Morris, a London-based cigarette manufacturer, created a New York subsidary in 1902 to sell several of its cigarette brands, including Marlboro. By 1924 they were advertising Marlboro as a woman's cigarette based on the slogan "Mild As May".
The brand was sold in this capacity until World War II when the brand faltered and was temporarily removed from the market. At the end of the war three brands; Camel, Lucky Strike, and Chesterfield surfaced and established a firm hold on the cigarette market.
In 1957, Reader's Digest published an article linking smoking with lung cancer. Phillip Morris took notice and soon began marketing a new Marlboro with a filtered end as a "safer" alternative to non-filtered cigarettes. Through a series of ads now aimed at males featuring rugged cowboys and other manly images, Marlboro quickly gained market share and saw their sales increase 5000 percent within 8 months of the ad campaign's premier.
Marlboro has continued their basic rugged cowboy ads since the 50's with great success.