Felt is a mass of wool and/or fur. It is not woven, but rather pressed and manipulated in a centuries-old process using hot water and steam to create the strongest, smoothest, lightest, most water-resistant natural fabric known. Each manufacturer of felt closely guards his exact felt making process and formula.
According to legend, St. Clement (the patron saint of felt hat makers) discovered felt when, as a wandering monk, he filled his sandals with flax fibers to protect his feet. The moisture and pressure from pounding feet compressed the fibers into a crude, though comfortable felt. Similar legends suggest that Native Americans or ancient Egyptians "discovered" felt by way of fur lined moccasins or camel hair falling into sandals.
To the hat industry, whoever was first is not as important as the fact that function well. They are durable, comfortable, and attractive. Enjoy your felt hat!