Felt is a non-woven fabric formed when sheep's wool or animal fur is subjected to heat, moisture and pressure or agitation. Soap, or an alkaline environment, helps the felting process. Heat and moisture cause the outer scales along the fiber to open, and the soap allows the fibers to slide easily over one another thereby causing them to become entangled. The wool fibers are made up of a protein called keratin. The keratin in the fibers becomes chemically bound to the protein of the other fibers thereby resulting in a permanent bond between the fibers, making the felting process irreversible.
The Romans and Greeks knew of felt. Roman soldiers were equipped with felt breastplates (for protection from arrows), tunics, boots and socks. Today felt is still in use in many parts of the world especially in areas with harsh climates. In Mongolia, nomads live in felt tents called yurts or gers. In Turkey, rugs, hats and other items are made of felt. In South Central Asia nomadic tribes use felt as tent coverings, rugs and blankets. Shepherds use felt cloaks (kepenek) and hats to protect them from the harsh climate. In Scandinavia and Russia, felt boots are produced and widely used.