The Republic by Plato Part 2 Page 46

little use for any other purpose; their duty is to be in the market, and to give money in exchange for goods to those who desire to sell and to take money from those who desire to buy.

This want, then, creates a class of retail-traders in our State. Is not ‘retailer’ the term which is applied to those who sit in the market-place engaged in buying and selling, while those who wander from one city to another are called merchants?

Yes, he said.

And there is another class of servants, who are intellectually hardly on the level of companionship; still they have plenty of bodily strength for labour, which accordingly they sell, and are called, if I do not mistake, hirelings, hire being the name which is given to the price of their labour.