The heart is an interesting thing. Some of what we still believe about the heart originated in ancient Egypt. They believed the heart was the source of wisdom, emotions, memory, the soul, and personality. Interestingly, they believed the only purpose of the brain was to pass mucus to the nose.
Even now, we use “heart” the way the Egyptians did. Sayings – like take heart, have a heart, heartbreak, faint of heart, my heart goes out, open one’s heart, pour out one’s heart, heart grows fonder, heart sick – show that the heart really is at the center of all of our emotions.