In the beginning, there were Levi's. In 1853, during the heart of the gold rush, a Bavarian émigré named Levi Strauss arrived in San Francisco from New York, looking to expand his family's East Coast dry-goods business. Among his wares were blankets, cloth by the yard and durable work pants, sometimes called "jeans pants." Then in 1872, one of Strauss's customers, a tailor named Jacob Davis, made him the offer that would change his fortunes — and the way Americans dressed — forever. Davis had been buying Strauss's blue denim and duck cloth to sew "waist-overalls" and had perfected a method of reinforcing them with the same copper rivets he used on horse blankets. Unwilling to put up the $68 necessary to patent his creation, he suggested that Strauss pay the fee in exchange for a half-interest in the business.

The patent for "improvement in fastening pocket-openings" was granted in 1873, and soon after Levi Strauss & Company opened its first San Francisco factory to manufacture bluejeans. The original design, which was simply called "XX," was eventually assigned lot number 501. Competition was fierce: In addition to an upstate New York company called Sweet-Orr, founded in 1871 (which may actually have been the first commercial jeans producer), there were countless regional jeans companies by the turn of the century, including Osh Kosh B'Gosh in Wisconsin and Carhartt in Michigan. In 1911, the H.D. Lee Mercantile Company of Kansas started producing its own brand of workwear, which eventually led to Lee Dungarees. Along with Wrangler (originally founded in 1904 as the Hudson Overall Company of Greensboro, N.C.) and Levi's, Lee went on after World War II to become what James Sullivan, author of "Jeans: A Cultural History of an American Icon," calls "the big three" of bluejeans.