Felt hat making was one of the earliest important American industries. The raw materials (wool, beaver and other furs) were plentiful; the skills for working wool and fur into felt and felt into hats had crossed the Atlantic with the colonists, and profitable markets existed both at home and abroad. As early as 1731, colonial hat makers were supplying a significant proportion of the needs of the colonies and also exporting to Spain and Portugal in such quantities that London felt makers considered their own markets threatened. The British Parliament tried to protect those markets by passing the Hat Act prohibiting colonial export of hats and limiting hat production.