I'm not an expert, but I believe it depends on what part of the world you were in. The oldest carpet that still exists to this day is from the 5th century BC in Armenia, and there is evidence of sheep and goat shearing as far back as the 7th. As far as I remember, the Islamic empire/influence spread the idea of rugs to the places they conquered(probably getting the idea from Persians, Turks, and Armenians, who have the oldest carpet remains of any civilizations). In the 16th century, so-called "Turkish style" of decorating rooms with heavily decorated carpets became popular with French nobility, and soon afterwards looms were introduced to England. However, full room carpets remained a luxury item until well after WW1. During the last three quarters of the 20th century manufacturers began being able to mass produce carpets via modern manufacturing techniques, prices dropped, and poorer people were able to afford them, causing a kind of boom. Since the 40s they have become the norm, especially in the US.