Under Edward III a flourishing trade in wool grew up between England
and Flanders. The manufacture of fine woolen goods was also greatly
extended in England. All commerce at this period was limited to
certain market towns called "staples."
To these places produce and all other goods for export had to be
carried in order that the government might collect duty on them before
they were sent out of the country. If an Englishman carried goods
abroad and sold them in the open market without first paying a tax to
the Crown, he was liable to the punishment of death. Imports also
paid duties.