Though it has been documented that the practice of medicine dates as far back as 3000 B.C., Hippocrates is often dubbed as the "Father of Medicine" for his long-lasting contributions to the discipline (despite the fact that he lived in the vicinity of 400 B.C.).
Most who are familiar with the name Hippocrates are likely to attribute this to the famous "Hippocratic Oath," which continues to be used by some schools, at least in part, as a ceremonial component for graduating medical students. Of course, however, the classical version of this oath has been modified to several different more modern versions to represent current ethical stances.
It is important to note, however, that the development of the Hippocratic Oath is not the sole reason for which Hippocrates has received the designation of the Father of Medicine. A vast collection of work known as Corpus Hippocraticum, or Hippocratic Collection, also carries his name -- though the precise authorship is not clear, it is believed to be not solely his work, but rather that of many scholars and of his students as well.
The Corpus Hippocraticum contains a large body of medical literature in various forms and represents the beginning of medicine in many ways. It is in this body of literature where the Hippocratic Oath and other matters such as epidemiology and the status of medicine are described and discussed.
While the practice of medicine may have preceded the Corpus Hippocraticum in some shape or form, physicians remain indebted to this vast collection of work, as the conduct of physicians and their place in society today has been undoubtedly shaped by the teachings of the sometimes forgotten Corpus Hippocraticum.