In common-law countries, they are often grouped by medical specialties (cardiologists, family doctors, etc.).
A professional or college official is a public corporation of an industry association composed of persons exercising liberal professions and calls are usually covered by the state.
It is believed that Opificum o Societate colleges, from which the current Official Colleges, were derived from the associations of commoners to achieve benefits similar to those enjoyed by the patricians, needed a special authorization from the Emperor or the Senate to take legal personality.
From Alexander Severus, these associations are transformed to free compulsory, children should follow the profession of his father.
In Europe, and specifically in Spain, colleges and professional associations have a long tradition through the centuries, interrupted only by the French Revolution, which in its ideology advocating that there should be one between the citizen and the sovereign state.