Merchants and craftsmen
The most important persons in a town were the merchants. They fixed the taxes to be paid by people coming into the town to sell goods. They set the laws for the markets. They tried to make sure that no-one cheated or stole.
Merchants were traders who got rich by buying and selling goods. They bought wool, corn, and skins from country people. Then they sold them at a profit, sometimes to traders from abroad at trade fairs. These were big markets, where merchants met to buy and sell their goods.
Craftsmen were skilled workers. They made shoes, pots, swords, hats, etc. The most important of them were the men who owned the workshops. They were called the masters. But each craftsman began as an apprentice, living in the master's house and learning in his shop. When he was old enough and skilled enough, he became a journeyman. Now he worked for real wages, paid by the master. Every journeyman hoped one day to be a master.
By the thirteenth century, each town had a guild for each of the main trades. And the craftsmen had to belong to the guilds. (All the stocking-makers in York had to belong to the York hosiers' guild. All the leather-makers in Newcastle were in the Newcastle tanners' guild.)
A group of masters was in charge of each guild. They said how the goods should be made and what the prices should be. They made rules about what the apprentices had to learn. They gave money to members who were ill, and paid pensions to the widows of members who had died. The masters of most guilds were men, but some (such as the silk-makers of London) were women.
Walter Robson: Medieval Britain; Oxford University Press, 1991/2000, page 72