Hippocrates

Hippocrates, the Greek physician, who became known as the "Father Of Medicine", lived at a time when medicine was emerging from theurgy and philosophy into a distinct discipline in its own right. Until then, medical matters were in the hands of religious leaders. This led to the idea that some illnesses -- for example: epilepsy -- were caused by the gods, rather than natural causes.

Hippocrates was probably born around 430 BC on the Greek island of Cos and probably died around 370 BC. If so, that's a pretty good pedigree, as it means he lived to be ninety years old.

One of the pillars of Hippocrates's medical philosophy was the idea of a method of systematic observation of the patient. This is now know as "clinical observation".

What is most remarkable about his discoveries is the accuracy of his remedies for various ailments, which are only now -- two and half thousands years later -- being scientifically proven. For example, he prescribed eating liver to aleviate night blindness. Yet it is only in the 20th century vitamin A was discovered. And vitamin A  -- found in liver -- is necessary to prevent night blindness.