Prominent Greek physician, surgeon, and philosopher Claudius Galen (ca. 131–ca. 201) wrote De temperamentis based on Hippocrates’ medical theory of the four humors—blood, phlegm, yellow bile, and black bile—to which he added the qualities dry, moist, hot, and cold in reference to the four elements (air, water, fire, earth). He described four basic human temperaments: "sanguine” disposition was hot/moist and associated with blood; "choleric" disposition was dry/hot and associated with and yellow bile were dry/hot; "melancholic" disposition was cold/dry and associated with black bile; and "phlegmatic" disposition was moist/cold and associated with phlegm. In combination, a balance of these elements and temperaments would foster better health. Galen was an accomplished medical researcher of antiquity and influenced the development of anatomy, physiology, pharmacology, and pathology.