How did a medieval doctor come to his position?

Answer 1

Medieval doctors learned their medicine in schools. One of these, the Medical school at Salerno, was formed out of earlier schools that moved to Salerno during periods of unrest in the 6th century, and these earlier schools dated back to the Roman Empire. Other schools of medicine were formed based on ancient medical practice or Arabic science in other places, such as Baghdad and Cordoba. The universities that opened in Western Europe beginning with in the 11th century usually taught medicine. These followed other universities that operated in the East, notably the University of Constantinople, which opened in 425 AD and remained open until the fall of the Byzantine Empire in 1453.

One of the important developments of the medieval universities was that they provided standard degrees which were recognized over nearly all of Western Europe.

The medical school at Salerno, by the way, has been turned into a university and is open to this day.