The Wealth of Nations by Part 3 Chapter 3 Page 20

A city might in this manner grow up to great wealth and splendour, while not only the country in its neighbourhood, but all those to which it traded, were in poverty and wretchedness.

Each of those countries, perhaps, taken singly, could afford it but a small part either of its subsistence or of its employment, but all of them taken together could afford it both a great subsistence and a great employment. There were, however, within the narrow circle of the commerce of those times, some countries that were opulent and industrious. Such was the Greek empire as long as it subsisted, and that of the Saracens during the reigns of the Abassides. Such too was Egypt till it was conquered by the Turks, some part of the coast of Barbary, and all those provinces of Spain which were under the government of the Moors.