Also known as the Oregon State Bar:

The number one purpose of the craft guild is to protect the economic interests of its members. Rules regulate membership and trade. In the early days, no artisan could work in a town unless he was a member of the local guild. No goods could be imported into a town if they competed with local products. It was in this way, that the local guilds held a monopoly of the market within its own town. Competition amongst members of the same guild was discouraged and the guild would do almost anything to prevent it. Each guild laid down detailed regulations governing the quality of its product, the methods of manufacture, and the price that could be charged for it. These regulations were meant to promote the ideal of every member of the guild making exactly the same thing by the same methods and selling it at the same price. Even the hours of labor were rigidly controlled. For example, a member of a guild where careful, difficult work was required was not allowed to work before sunrise or after sunset.

With the power of a monopoly structure behind them, the craft guilds can obviously abuse their power by lowering the quality of their goods and raising the prices. It is up to the government to step in and oversee the guilds. In England where the royal government is strong the more important guilds are carefully supervised. The English government sets the weight, quality, and price of loaves of bread and the quality and measure of ale. Strict regulations for the making of cloth have been laid down and enforced by governmental inspectors. In France the guilds are more likely to be controlled in cities where the lord is powerful. The regulations of most guilds within Paris have to be approved by the royal provost and he is then responsible for seeing that the guild officers enforce them. Other various dignitaries control the other guilds. For example, the booksellers and ink makers are ruled by the rector of the university, the makers of candles and sacred vestments by the bishop, and the wine dealers by the royal butler. Unfortunately in self-governing towns control is difficult and the guilds tend to abuse their monopolies rather freely.