On this date in 1873, Levi Strauss first patented his denim pants—better known as blue jeans.
Strauss moved to San Francisco, Calif., in 1853 with the purpose of opening a dry goods store. Customers told him a good strong pair of pants was hard to find, so he started making trousers out of canvas. When the customers complained about chafing, Strauss switched to twilled cotton made in Nîmes, France. Called “serge de Nîmes” at the time, it would later be known as denim. A customer named Jacob Davis began to market Strauss’s pants. The two entered a partnership and had their “blue jeans” patented on May 20, 1873. The duo received U.S. Patent No. 139,121.