courage (n.)

c. 1300, corage, "heart (as the seat of emotions)," hence "spirit, temperament, state or frame of mind,"from Old French corage "heart, innermost feelings; temper" (12c., Modern French courage), from Vulgar Latin *coraticum (source of Italian coraggio, Spanish coraje), from Latin cor "heart" (from PIE root *kerd- "heart").

Meaning "valor, quality of mind which enables one to meet danger and trouble without fear" is from late 14c. In this sense Old English had ellen, which also meant "zeal, strength." Words for "heart" also commonly are metaphors for inner strength.

In Middle English, the word was used broadly for "what is in one's mind or thoughts," hence "bravery," but also "wrath, pride, confidence, lustiness," or any sort of inclination, and it was used in various phrases, such as bold corage "brave heart," careful corage "sad heart," fre corage "free will," wikked corage "evil heart." 

The saddest thing in life is that the best thing in it should be courage. [Robert Frost]