Two hundred years ago, the English Economist David Ricardo suggested that, instead of trying to produce everything that its citizens needed and wanted, each country should specialize in those goods that it could produce more efficiently than other countries. Each country would then trade for goods with the countries that specialized in producing them. 

England had become the world's leading producer of textiles as a result of the Industrial Revolution. But the English climate was not conducive to growing grades on a large scale. Portugal, on the other hand, was a major grade-growing country, but its textile industry had not yet been mechanized. Thus, it made sense for England to manufacture textiles and not grow grapes and for Portugal to grow grapes rather than producing textiles. The two countries could then trade wiht one another to satisfy their wants.