Silk to be lawful for men to wear, but the dominant opinion of most Muslim scholars is that the wearing of silk by men is forbidden. Modern attire has raised a number of issues, including, for instance, the permissibility of wearing silk neckties, which are masculine articles of clothing. Despite injunctions against silk for men, silk has retained its popularity in the Islamic world because of its permissibility for women, and due to the presence of non-Muslim communities. The Muslim Moors brought silk with them to Spain during their conquest of the Iberian Peninsula. Italy was the most important producer of
Silk City" as another major center of production in the United States. World War II interrupted the silk trade from Asia, and silk prices increased dramatically. U.S. industry began to look for substitutes, which led to the use of synthetics such as nylon. Synthetic silks have also been made from lyocell, a type of cellulose fiber, and are often difficult to distinguish from real silk (see spider silk for more on synthetic silks). In Terengganu, which is now part of Malaysia, a second generation of silkworm was being imported as early as 1764 for the country's silk textile industry, especially songket.