the first denim trousers were made in Genoa, Italy (Gênes).
however, denim initially gained popularity in 1873 when, Jacob Davis, a tailor from Nevada, manufactured the first pair of “rivet-reinforced” denim pants. His concept for making reinforced jeans was inspired when a lady customer requested a pair of durable and strong pants for her husband to chop wood. Davis was overwhelmed with the demand of denim jeans. He soon sold 200 pairs to workers in need of heavy work clothing and the demand came out hand that Davis made a deal with Levi Strauss and Co. (manufacturer of denim linen) to patent his copyright to manufature denim jeans thus, in large quantities.
Basically, denim pertains to masculinity but in the 60s, old denim jeans were recycled into long denim skirts, by opening the inseams, and inserting pieces of triangular denim (or any other fabric) in the front.
Nowadays, denim had been massively worn unisexually in any form of classification, jeans for men and women, jackets, skirts, so on and so forth.. But to obtain a more feminine look on denim, Ray Cassini, an italian designer tailored a denim dress adding it with a touch of lace ...because reflecting to what mayo says, lace for one good reason it enlivens an otherwise slightly boring black, plain & other grumpy colors.