The purpose of this chapter is to evaluate and quantify the ways in which the immigrants’ presence and manufacturing skills contributed to the development of the cloth industry in fourteenth-century England. In order to do so, the scale of the immigrants’ contribution to the industry will be examined through the number of workers, as well as the types of cloth they produced in England. The know-how they exhibited in the host country will be compared with their involvement in the textile industry of their home county prior to exile. Finally, the chapter will touch upon the immigrants’ mercantile activities and assess how their involvement in the trade in cloth and wool allowed them to increase profits and ensure control over the whole production process.