Hippocrates also believed that there were four humours: blood, black bile, yellow bile and phlegm. Each humour was associated with seasons and elements of the Earth, and Hippocrates believed that these four humours had to be balanced in order to be healthy.
Hippocrates encouraged doctors to record information and taught people to stop relying on the Gods. He created the Hippocratic Oath—a promise to provide healthcare regardless of background, confidentiality and to treat the ill to the best of one's ability—and although he