The concept of professionalism has undergone major changes over the millennia in general and the last century specifically. This article, the first in a series of articles in this Journal on professionalism, attempts to provide the reader with a historical overview of the evolution of the concept of professionalism over time. As a result of these changes, medical school curricula, and contemporary specialist training programs are increasingly becoming competence based, with professionalism becoming an integral part of a resident's training and assessment program.