Closed, flat-soled slippers worn by pontiffs only at pontifical solemn mass and related functions; they were of various colors, including liturgical colors, throughout the centuries. They are not sandals. They are worn with liturgical stockings. The privilege of wearing the slippers and stockings belongs only to bishops, abbots, and other prelates by special privilege from the pope. Use of the slippers has fallen out of common use since the Second Vatican Council.