Mules not only came in different styles and various decorations, but also can be categorized by distinct types. In the nineteenth century, two male slippers were very popular mules. In the late 1880s, a very popular version of the mule at the time in England was the Albert. In addition to the Albert, the Alfred was also a man's boudoir, or morning slipper. This name comes from Daniel Green and Company 1892's "Alfred Dolge's Felt Slippers and Shoes."
