Felting is the process of shocking wool with temperature changes and agitation until it forms a solid fabric without having to first weave or spin it. Fulling uses the same techniques, but starts with a completed fabric or object.
The patron saint of felters (and hat makers) was St. Clement (Not Pope St. Clement I), who was said to have filled his shoes with unwoven wool in order to cushion his feet as he wandered. As he walked, the moisture and pressure from his feet compressed the fibres into felt. However, archaeology has shown felting was already being done during the Bronze age.