Between 1781 and 1789, silver spectacles with sliding extension temples were being fabricated in France; however it was not until the 19th century that they gained extensive popularity. John McAllister of Philadelphia began fabricating spectacles with sliding temples containing looped ends which were much easier to use with the then-popular wigs. The loops supplement the inadequacy of stability, by allowing the addition of a cord or ribbon which could be tied behind the head, thus holding the eyeglasses firmly in place.