Guilds

A guild is a professional association of artisans and merchants who oversee the practice of their craft/trade in a particular territory. The word derives from medieval Europe where guilds were probably at their most extensive, but it has been used to describe similar groups before and after that period and in other parts of the world. Typically the key "privilege" was that only guild members were allowed to sell their goods or practice their skill within a city. There might be controls on minimum or maximum prices, hours of trading, numbers of apprentices, and many other things. Critics argued that these rules reduced free competition, but defenders maintained that they protected professional standards.

Wikipedia →