Felt from wool is considered to be the oldest known textile. Many cultures have legends as to the origins of felt making. Sumerian legend claims that the secret of feltmaking was discovered by Urnamman of Lagash. The story of Saint Clement and Saint Christopher relates that the men packed their sandals with wool to prevent blisters while fleeing from persecution. At the end of their journey, the movement and sweat had turned the wool into felt socks.
Feltmaking is still practised by nomadic peoples (Altaic people: Mongols; Turkic people) in Central Asia, where rugs, tents and clothing are regularly made. Some of these are traditional items, such as the classic yurt (Gers), while others are designed for the tourist market, such as decorated slippers. In the Western world, felt is widely used as a medium for expression in both textile art and contemporary art and design, where it has significance as an ecologically responsible textile and building material.
In the wet felting process, hot water is applied to layers of animal hairs, while repeated agitation and compression causes the fibers to hook together or weave together into a single piece of fabric. Wrapping the properly arranged fiber in a sturdy, textured material, such as a bamboo mat or burlap, will speed up the felting process. The felted material may be finished by fulling.
Only certain types of fiber can be wet felted successfully. Most types of fleece, such as those taken from the alpaca or the Merino sheep, can be put through the wet felting process. One may also use mohair (goat), angora (rabbit), or hair from rodents such as beavers and muskrats. These types of fiber are covered in tiny scales, similar to the scales found on a strand of human hair. Heat, motion, and moisture of the fleece causes the scales to open, while agitating them causes them to latch onto each other, creating felt. There is an alternative theory that the fibers wind around each other during felting. Plant fibers and synthetic fibers will not wet felt.
Needle felting is a method of creating felted objects without using water. The special needles used to make 3D sculpture, jewelry, adornments and 2D art have notches along the shaft of the needle that catch fibers and tangle them with other fibers to produce felt. These notches are sometimes erroneously called "barbs", but barbs are protrusions (like barbed wire) and would be too difficult to thrust into the wool and nearly impossible to pull out. There are many sizes and types of notched needles for different uses while working. Needle felting is used in industrial processes as well as in individual crafting.