Two millennia ago, Hippocrates classified skin diseases as either idiopathic, originating from the skin, or exanthematic, resulting from imbalances in the 4 humors: blood, yellow bile, black bile ...

Among the practices that the Romans adopted from the Greeks was the theory of the four humors, which remained popular ... who lived from 4 C.E. to around 70 C.E., was an agricultural writer.