Analysis of information sources in references of the Wikipedia article "길드" in Korean language version.
[...] a cognitive basis of any kind had to be at least approximately defined before the rising modern professions could negotiate cognitive exclusiveness — that is, before they could convincingly establish a teaching monopoly on their specific tools and techniques, while claiming absolute superiority for them. The proved institutional mechanisms for this negotiation were the license, the qualifying examination, the diploma, and formal training in a common curriculum. The typical institutions that administered these devices were, first, the guild-like professional association, and later the professional school, which superseded the association in effectiveness. [...] Obviously, none of this was in itself an organizational invention. The guilds of merchants that sprang up in eleventh-century Europe were also voluntary associations tending towards the monopolistic control of a new form of trade.[...]
