Denim – an anglicisation of the French “serge de Nîmes” – is a cotton twill fabric that has been used to make workwear since the 17th century. Cotton twill is comfortable, hardwearing, and economical to produce. These qualities are ideal for workwear, especially items of clothing that will be worn for many hours every day. Testament to the importance of the quality of fabric, the original denim jeans produced by Levi Strauss & Co. were named XX in honour of the cotton twill they were constructed from. It came from the Amoskeag Manufacturing Company in Manchester, New Hampshire, and was considered to be the best of its kind. Those same jeans would later become known as Levi’s 501. The unique appearance of indigo denim is the result of dyeing only the outside surface of the warp and leaving the weft white (warp-dyed) so that, as the denim wears, its colour fades to off-white. This patina has become so desirable that techniques have been developed to artificially wear away the surface in a controlled fashion, such as with abrasive and chemical washing.