Beginning of medicine dated back to 500,000 BC when ancestors of man protected themselves against diseases with primitive medicine. In ancient Greece, Asclepius was considered the God of medicine and Hypocrites, the Father of medicine, emphasized the material base of the function of the human body. Medical knowledge progressed in the 16th and 19th centuries with the discovery of diseases such as Smallpox, cholera, and scarlet fever. Progress in the 20th century can be seen through improved hygienic conditions and an increase in average life expectancy.