Levi’s have been the most famous brand of jeans and denim clothing for decades. Levi Strauss & Co. was founded in 1853 when Levi Strauss emigrated from Germany to San Francisco to help with his brothers’ dry goods business. The company began producing denim overalls in the 1870s but did not start making jeans until the 1920s. Strauss and his partner Jacob Davis patented the copper rivet to reinforce clothing in 1873. It was to become a key part of their jeans design. The demand for their jeans skyrocketed in WWII. This saw their sales staff grow from 15 before the War to 22,000 in 35 countries just after it. Levi's jeans became popular with young people in the 1950s and ‘60s. The 501 was then, and is today, their biggest-selling product. The company leads the fashion industry in the number of trademark infringement cases.