Complex sentence: Formerly, leggings were two separate garments, one for each leggings are typically made from a blend of lycra (aka spandex), nylon, cotton, or polyester blend, but they can also be made from wool, silk and other materials.
Split into simpler sentences: Formerly, leggings were two separate garments, one for each leg. Modern leggings are typically made from a blend of lycra (aka spandex), nylon, cotton, or polyester blend, but they can also be made from wool, silk and other materials.